Upgrade to Xtext 2.7 fix #88 #89
* make custom lexer compatible with 2.7
* fix build
Add antlr-src, antlr-source and source as grammar folder container, fix #87
Lexer grammars: explicit tokens not recognized inside type() action, fix #85
Fix #83 Pareser Tree view: tokens file not found when using separate lexer and parser grammars
update latest dependencies, fix #74
 syntax highlight for python targets fix #97
upgrade to ANTLR 4.4 fix #98
Parse tree: Add support for imported grammar fix #93