Adding font-lock for function parameters

This commit adds font-lock for highlighting function parameters like
 &optional etc.
Merge pull request #13 from theanalyst/feature/fnparam-font-lock

Adding font-lock for function parameters
Adding keywords introduced in hy-0.9.11

Syntax highlighting for functions introduced in 0.9.11
Merge pull request #14 from theanalyst/kw911

Adding keywords introduced in hy-0.9.11