Provide more details in the illegal error message.

Conflicts:
	src/highlight.js
More capable SUBST in strings
More robust regexp support for CoffeeScript
Builtin keywords in CoffeeScript
Tuning CoffeeScript relevance.

- Zeroed relevance of single-quote strings
- Added a few characters into illegals for classes
Removed redundant line from CoffeeScript snippet
Added Cédric Néhémie to contributors