SVGHMI: non significant cosmetic changes

- New widget customHtml which allows to insert block of html code
- widget animate transfered to animaterotation
- widget animate, left to be more customizable
- changes to svghmi_v2/svghmi.svg

PY_EXT: OnChange is now a coma separated list of callables. Updated tests/python accordingly.

Button fix if no active or inactive state,
Widget animate changed to use anitmateTransform and added option to change rotation
Widget circular slider fixed so it is working on got and reprogramed so it similar to normal slider
Widget slider added support for changing size still need some changes to work properly
Added slider to svghmi test project
Changed svg in svhgmi_v2 project

Merge two different heads

SVGHMI: Documentation fix

Button and toggle reworked to use animate and dispatch
Slider added buttons to incremente/decrement by 1
Init for animate widget
Changed test svg and plc

Merge + fix side effects of making warning instead of errors in case of missing HMI variable

Updated svg and xml for testing program

Button, ToggleButton and slider updated. Error to warning when building

Button fixed so it doesn't release until it gets feedback from plc

Toggle button changed so it makes changes instantly. There was too big delay if we waited for feedback.

Slider added new features need some changes for final version.

Modbus: fixed typo in ctype typing.

MODBUS: Fix saving of websettings.

Runtime/PLCObject : move call to PreStartPLC right after call to the "start" method of all python extensions, and then just before the start of the python loop executing python_* blocks.

SVGHMI: Better error message when inkscape is not installed.

SVGHMI: nicer error message

Merge

Attempt to workaround problem reported about empty plc.xml after unrelated crash. Now, if etree model is corrupted in a way tostring() would generate an empty string, exception prevents saving.

SVGHMI: JsonTable can now have clickable elements, that trigger a request with extra argument whose content is taken from Json data.

Merged

SVGHMI: cosmetic fix in test

All widgets reworked to use widget class and animate function if needed

SVGHMI: Moved JsonTable/Alarm related test in a separate page.

SVGHMI: JsonTable now ignores elements and groups starting with #

SVGHMI: Fix keypad : non-number input was always considered invalid because of missing type checking.

SVGHMI: JsonTable now updates range and position variables so that slider widget can update.

SVGHMI: Fix multiple variable support in widget

SVGHMI: Add TODOs in Button widgets.

SVGHMI: Alarm test not using Button widget anymore, too many problems. Use Input widget instead to increment value on each click and execute python code on change.

SVGHMI: little fix in HMI:Button

SVGHMI: JsonTable now use intermediate variables again to address JSON data without duplicating code or referencing. Using intermediate variables also alows to check for availability of data and stop evaluating early if data is missing. Finally added complete roundtrip example to illustrate use of JSonTable to display "alarms" collected in python from changes on PLC boolean variables.