added spark library file
added lexer_generator to Lexer class
Merge branch 'master' into lexergenerator
refactored Lexer.__call__ and match
added basic lexer_generator implementation
fixes comments
Merge branch 'master' into spark

Conflicts:
	README.md
Merge branch 'master' into spark
moved spark source to external dir
python3 syntax
pep8 and other small fixes
deleted ply example redundant file
fixed typos
improved debug message
added ply calculator example
added PLYTranslator
updated to the latest version
Merge branch 'master' into spark
upgraded to version 0.2.0
fixed indentation