Simple todo.

Required for initial self-hosting:
 
  * NONE! We are selfhosted now!

Required for full implementation:
  * Handling #line directives.
  * A LOT OF DOCUMENTATION.
  * Add tests for Trans::C independent from 06-emitter.t
  * Add tests for dynamic mode of Emitter.

Nice to have:
  * Profiling and performance tuning of ops parsing (we need pmichaud).
