Internal refactor, dce support, removed dependencies, only assert in debug.

- Updated license copyright years.
- Removed dependencies (used functions not worth the overhead)
- Removed support for haxe 2.x
- Only throw exceptions in debug mode.
- Refactored injection points so they are ignorant of rtti metadata stucture.
- Added support for dce by marking injected types with @:keep metadata
- General cleanup