PYTHOOOOOOOOOOON

This was dying when rendered through the HTML formatter because
the HTML formatter calls translate on returned strings. Turns out
the implementation of translate on 'unicode' objects is COMPLETELY
different to the implementation on 'str' objects AND THIS IS ONLY
VAGUELY MENTIONED IN THE DOCUMENTATION
don't expect nkw after a \ or λ
prettier highlighting for classes and defs
highlight singleton methods properly
highlight string interpolation properly
Merge pull request #86 from charliesome/fix-slash-lexer

Fix slash lexer