* Refactor: Implement the space key as an editing action
The space key is no longer a CHAR key but now an EDITING key. This
allows changing the behavior of the space bar while allowing custom
layout users to define a key outputing a space as before.
KeyModifier and ComposeKey are updated to treat the space key as before.
* Enter the best suggestion when the space bar is pressed
* Refactor: Implement backspace as an editing action
* Undo suggestion when delete is pressed
The delete key (backspace internally) undoes the suggestion if the last
action done was entering the suggestion with either the space bar or the
candidates view.
* Add an option to enable space bar autocomplete
This option is off by default. Undoing a completion with backspace works
in any case.
* Refactor: Track selection emptyness in CurrentlyTypedWord
This removes an expensive RPC call.
Jules Aguillon
df3594bd53