Simplify grammar
Fix error in simplification.
Fix AT2 highlighting.
Simplify NUMBER rule
Simplify HASH_IDENT
Commenting InnerExtend
Delete out of date comment.
Simplify LESS grammar
Update comment.
Organize imports.
Fix bug in token index
Delete BlockUtils.
Fix bug in token index.
Fix weird bug, probably an Xtext one.
Add TODO.
Revert validator.
Delete special handling of ';' in mixins.
Fix mixin rule.
Refactor @keyframes statements.
Simplify Mixin rule.