SVGHMI: update Makefile to pick all changes to any dependency

SVGHMI: created widget_*.ysl2. Renamed widget_common in widgets_common, so that it doesn't match globing.

SVGHMI: moving comments

SVGHMI: added widget_common.ysl2

SVGHMI: More readable debug output gen code

SVGHMI: Cosmetic changes

SVGHMI: added inline_svg.ysl2

SVGHMI: detachable_elements.ysl2 becomes detachable_pages.ysl2, and includes logic to process pages elements. Other minor code moves.

SVGHMI: moved debug code

SVGHMI: created detachable_elements.ysl2

SVGHMI: more debug code moved to hmi_tree.ysl2

SVGHMI : create hmi_tree.ysl2, rename bbox_intersect.ysl2 into geometry.ysl2 and move more code into. Add per included ysl2 file debug output.

SVGHMI: created bbox_intersect.ysl2

SVGHMI: Re-enable dispatch to arrays of functions in case of multiple suscription per widget. Still unused, but disabled for reasons not any more true.

SVGHMI: relative pages and page jumps

SVGHMI: take care of path given in HMI:Page and HMI:Jump, but do not apply subscription offset for now. Intermediate commit in a "working" state.

SVGHMI: significant whitespace changes

SVGHMI: unsignificant changes or changes in generated code

SVGHMI: Stop ignoring HMI_NODE in HMI tree, and count it as a BOOL. Soon we use those nodes as reference for relative page jump, and as an "enable" bit for features associated to an HMI tree fragment.

SVGHMI: cosmetic code moving

SVGHMI: split page switch into switching subscription and switching elements in the DOM, to ensure that subscriptions have been send before changing DOM, and avoid some flicker.

SVGHMI: fix wrong updates of HMI variables on each change, especially when not subscribed.

SVGHMI: whitespaces

SVGHMI: fixed repeated error when Input widget is missing 'value' element

SVGHMI: more decoupling in between UI related and the rest of JS code, still in the aim of enhancing robustness under heavy load.

SVGHMI: use requestAnimationFrame to delegate rendering of updates from network. Should help prevent browser collapse leading to watchdog in case of overload.

SVGHMI: Fix disapearing elements in case of nested detachable elements.

SVGHMI: Meter widget accepts 2 arguments : min and max, taken in account when min or max text element is missing

SVGHMI: More precise error message on missing HMI path. Meter widget now defaults 0-100 range when min and max elements arent's present, without error.

SVGHMI: more whitespace fixes

SVGHMI: unlink clones (i.e. deep copy elements refered by svg:use) inside widget.

Designer can use Inkscape clones to duplicate similar assets accross widget. Those clones are unliked so that elements can be independently transformed by individual widgets.

SVGHMI: whitespaces and comments

SVGHMI: completely fixed indentation of generated widget description. Lets try to keep it as-is until we can use yslt indentation.

SVGHMI: re-indent generated JS

SVGHMI: detach/re-attach elements required by pages on page switch

This is meant to optimize performances with large drawings leading to long restyle or reflow.

SVGHMI: re-indenting

SVGHMI: declares pages detachable requirements as an object, to find more efficiently common requirements

SVGHMI: fix some JS + add generation of detachable elements, to be continued

SVGHMI: now compute discardable elements first so that we can do better grouping of required elements when sumarizing.

SVGHMI : documentation for new geometry intersection computation code + little fixes...

SVGHMI: detachable and discardable elements sets, Reworked geometric intersection, toward more accurate page content detection.

Moved page's widget/element dependency crawling functions so that it is possible to compute a global detachable and discardable elements sets.
Reworked geometric intersection detection logic to distinguish ovelapping and inclusion.
Goal is to include englobing and overlapping graphical elements, but not groups (would then include everything around...). Intermediate commit, to be continued.

SVGHMI : still trying to optimize. Added xslt code to identitfy minimum set of elements needed by a particular page. Plan is to remove unseen/unused elements from the DOM, and re-appending them later when used, on page switch. Disabled previous optimization.

SVGHMI: attempt to optimize for webkit, because of really slow style recompute in svg:use : "unlink clones" (as in inkscape) but stop deep-copy when meeting a widget, and create a new clone instead.

SVGHMI: optimize browser work by hiding (display:none) pages that are not displayed.

SVGHMI: Better and less verbose SVG namespace handling in XSLT transform

SVGHMI: Added mostly untested switch widget

SVGHMI: HMI:Page can now be a svg:g group or a svg:use clone, and included/linked widget are included in page. HMI:Jump was updated to be clickable through svg:use, to be generalized.

SVGHMI: ensure that coordinate in CSV file generated by inkscape are both matching svg default unit and in default reference frame

SVGHMI : still behave, even if important things are missing in SVG widget definitions (ex: needle missing for Meter widget)

SVGHMI : fix watchdog exception when timeout null

SVGHMI: be a bit more tolerant with missing HMI paths or missing elements in widgets : continue build (with warning) and fail silently at runtime.

SVGHMI : fixed bug happening when some SVG ids are containing dashes

SVGHMI : wait for initial timeout after watchdog is triggered, since it generaly induces HMI restart

SVGHMI : watchdog is now taking an initial and interval duration as CTN fields.

SVGHMI : avoid caching of xhtml file by forcing cache-control header in http response.

SVGHMI : HMI_STRING now also supported from HMI to PLC

SVGHMI : cosmetic

SVGHMI non significant fixes

SVGHMI : support for HMI_STRING and HMI_BOOL

plc_debug.c/var_acces.c : whitespace cleanup and other cosmetic changes

SVGHMI : Added python fomating {port} and {name} to commands so that command can build target URL

SVGHMI : add on Start, Stop and Watchdog command fields to configuration

SVGHMI: added a watchdog. To ensure that the whole chain is checked, watchdog use a periodic echo of a hearteat variable. JS client code systematically register /HEARTBEAT at 1s update freq, and reacts on updates of /HEARTBEAT by systematically incrementing it. C code catch /HEARTBEAT update and feeds python-implemented watchdog. For now, watchdog does nothing when tiggered

Add --on-plc-start --on-plc-stop and --status-change to runtime command line, calling given command respectively on start stop or any event. Command line string is python formated (to eventually include status with {}) before being split (supports quoted strings) and passed to Popen for non-blocking execution.