Update Codemirror

* Codemirror 4.5
* angular-codemirror-ui 0.1.6
Fix Codemirror shortcuts

* Moving some keys from global listening.
* Move Codemirror keymap config to Editor class.
* Run $digest upon codemirror model update.
* Mac shortcuts fixed (Cmd-Up/Down/Enter)
Merge pull request #3067 from oskarhane/codemirror_keys

[master] Codemirror keys