Add support for true and false

--HG--
extra : amend_source : 9f9751b79e0192de78eade82f2f9277f443d5904
Distinguish in lexer between integers and floats
Allow strings as binding names
Add some examples of string, symbol in lexer source

--HG--
extra : amend_source : 1a3c0a35b8d0160d8c2d69def07093d617f3da7c
Add support for array literals