Improved structure and simplified extend support (safe one run)
Tweaked parser to deal with inline calls like other statement calls (name attribute for name instead of child)
Added system call support in expression. Prohit added for mixin includes in expressions.
Fixed unit test
Added new failing test
Improved flattening engine to ignore unused mixins
Improved compressor handling with left over mixins
Using custom exception type + improved errors
Improved exception
Error handling improvements
Used better exception types