TinyPG callable from command line

* refactor and isolate business code (aka parse/buil/eval) from
presentation (MainForm)
* add commandline support on Main() with branch to either GUI or Silent
run
TinyPG callable from command line

strip the StringBuilder from method parameters, it now stand as a
Program Property
TinyPG callable from command line

*bug correction
*add unit test
*code refactoring
Bugfix : default outputpath cause NullpointerException

* default outputpath was set to C# (langage default)
Merge branch 'refs/heads/bugfix2'
TinyPG callable from command line

*add some unit test