Emacs fixes 2014 03 12

A couple of emacs / occur / isearch related fixes

- Fixes bug introduced in 5e2c5f4 (emacs handler doesn't deal with key events when just modifiers are pressed)
- remembers emacs line mode when entering/exiting occur
- isearch handles paste: enter isearch (ctrl-s) then yank (ctrl-y or cmd-v / ctrl-v) or kill (ctrl-w -- kills the next word at cursor into isearch)