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.