Abstracted keyword to a class to make syntax highlighter code easier
Merge branch 'keyword_abstraction'

Conflicts:
	src/main/com/qq/coqide/syntax/highlighting/CoqSyntaxHighlighter.java
Completed Coq tokens lexer. Fixes #1.

Reference: http://coq.inria.fr/distrib/current/refman/Reference-Manual003.html