Issue11

Fixed issue #11. Control-key combinations should work now.

The commits should probably be `cherry-pick`ed into `master`.

New problems introduced: control-key combos clear the textbox's state, so, for instance. typing `k`, pressing `^a`, clicking to the right of `k`, and typing `o` will produce `kお instead of `こ`. 

This behavior makes more sense than the behavior _not_ clearing the state would produce. For instance, typing `k`, pasting in some text, and then typing `o` would replace the last character of the pasted text with  `こ`. (See also issue #16.)