jwrapper: New features added

This may be considered as the first release of jwrapper. Here's a list of the new implemented features since the last PR:
* Grep into `lib/android` to retrieve already wrapped classes
* Auto-generate licence
* Basic user interface added
* Choice between : 
  * Auto-wrap unknown types
  * Comment methods containing unknown types
ok. je comprends. Mais document au moins pourquoi le NIT_DIR est necessaire