Text watcher injection

Hello.

I know this pull request isn't ready to be merged, just want to receive some feedback and ask some questions:

1. Is is ok to use the `SimpleTextWatcher` hack to avoid methods stubs generation?
2. What is the right way to change a parameter type? At the moment you have to use `Editable`, but `String` or `CharSequence` is more desired.

		// now
		@OnTextChanged(R.id.input) void onTextChanged(Editable text) {
		  Toast.makeText(this, "Text changed " + text, LENGTH_SHORT).show();
		}

		// desired
		@OnTextChanged(R.id.input) void onTextChanged(String text) {
		  Toast.makeText(this, "Text changed " + text, LENGTH_SHORT).show();
		}