Better writing of some xpath added in previous commits about XSLT optimization.

Moved some definitions away from controller class, and adaped references them through all code.

Hook Beremiz Launcher AppStart to AdvancedSplash OnPaint event in order to ensure image is beeing displayed before loading.

Avoid endline escaping in multiline xpath epressions in xslt. '
' Is apparently ignored but never know...

Fixed earlier XSLT optimizations. Some/most results were missing.

Moved some code from PLCController.py to other modules. Added necessary imports.

GetPouVariables optimized with XSLTModelQuery

Added /plcopen/InstancesPathCollector.py, to move more model xslt querying code away from PLCController.py.

Fixed Exception dialog disapearing after a view second when exception occurs during app startup.
Problem was caused by splashscreen timeout, wx closing averything else if there is no more main frame.
Changes:
- no more timeout for splashscreen
- use wx.App OnInit method to give first operation to mainloop, object are then now created in mainloop
- main loop is then created _before_ showing splash screen
- no more wxyield or wx processevent tricks needed to display splash screen
- exception handler not blocking anymore on dialog (callafter)
- because of mainloop being there before everything, exit must be called explicitely if exception caught during startup -> exit parameter in handle_exception + try/except around startup calls

UNTESTED ON WINDOWS

Moved XSLTModelQuery class to own module in plcopen package.

Added a class to speedup all XSLT queries. WIP, now only for instances_path.xslt / GetInstanceList()

Stripped useless node creation in instances_path stylesheet.

This should really help GetInstanceList to perform better: resolver removed, no more deepcopy, no more useless xml serialization, no more node-set() calls.

YSLT auto indent trick is useless here, added yslt_noindent.yml2, regenerated XSLT files

Prevent compiling XSLT on each call of GetInstanceList. To be continued. More optimization needed here. 100x would be fine...

Changed meaning of -c commandline argument for Beremiz service : only gives DEFAULT wamp config.
If existing project already has a wamp config, it is taken instead.

Factorized duplicated code

Better variable naming, and small optimization.

Unclutter graphics package scope.
Moved some import statements from "graphics" package to "viewer" module.
It also avoid systematic import of everything in graphics when we only need one submodule.

Removed dead code

Fixed pyro timeout for runtime, was set too short and runtime was disconnecting when building PLC

Ask to stop PLC before transfer if it is running

Factorized some repeated refresh code into a method, to allow customisation.

Launcher : add a debug attribute, instead of BMZ_DBG, so that customization can use it.

Stripped old dead code.

More changes in Launcher. Modules to be loaded in the background are given in a list, and assigned as object attributes. Also splitted CreateUI into CloseSplashScreen and CreatueUI.

ClassImporter now accepts string, callable or class, for compatibility with some old extensions.

Launcher: ShowUI call moves from preStart to start. ShowUI() split into CreateUI() and ShowUI(). Start()'s arguments are passed to CreateUI()
This is meant to allow customizations to pass own pre-instanciated controller to UI at startup.

Launcher: allows customizations to specify what globals passed to extensions

Documentation

Another set of meaningless changes to satisfy PEP8 and PyLint.

PEP8 conformity for modbus. Most of it done by autopep8, plus some easy refactoring.