EtherCat master plugin : commit changes recovered from KOSMOS 2018 installer, unkown author(s).

Add FatalError() method to ConfigTreeNode.
Extensions can report error addressed to user, without a traceback.

Fixed one more sequel of marking temporary variables created while generating ST code out of FBD

Changed yslt_noindent.yml2 again

Non significant changes in generated xslt, side effect of changes in yslt_noindent.yml2

More customizations to yslt

PLCobject: Call "stop" and "cleanup" methods from python runtime files in reverse order compared to "init" and "start".

Non significant changes to mute GCC warnings about unused variables.

Fixed sequel of earlier commit in PLCGenerator.py. Some ref to temporary variables are still not using the _TMP_ prefix. They are quite hard to find, so to be continued...

variable access code moved from plc_debug.c to targets/var_access.c for easiewr re-use in ext.

Swap CTN code gen and Libraries code generation order. In general library part of an extension needs to be computed before CTN part.

yslt_noindent : Avoid YSLT's indent logic to interfere when using linequote.

Add marker to temporary variables created while generating ST code out of FBD, so that they can be recognized as such.

Allow using docutil.get_inkscape_path() on Linux also.

Moved XSLT model query python code so that XSLT part can be reused for other transformations