Allow Ctrl behaviour to override layout

[kittsville]

The Ctrl key is oft used for keyboard commands and Chomskey currently doesn't support Ctrl based layout modification (only Shift and Alt Gr). Chomskey however still prevents the key's default behaviour if the key being pressed (e.g. 'a') has a mapping. This is annoying.

Fix: Add check to Chomskey object to force defaulting if Ctrl has been pressed