Character level diff cause weird editing behavior

[Soreine]

The Editor sometimes register a key twice as we type. Might be linked to performance issues that delay the EditorState update while typing ?

[Soreine]

On the branch no-decorator-set, we don't set new decorators on the EditorStates, and the repeated keys issue disapears. It seems not to be related to performances issues, because the Editor behaves well, even with slow updates.

[Soreine]

Linked to issue facebookarchive/draft-js#414