Make contact names editable in the GUI, but sadly quite hacky as yet :

It won't update merely because the user changes the name, users must actually
press enter or maybe click somewhere.  Ideally, some destroy event should
triger the update or something.

I suppose c.save() should not be called at some point, but presumably
not just because the user types by accedent, probably use whatever triger
changes contact.name.

I have not yet found any nice way to update the sidebar because actually
mainUI builds it, probably needs refactoring.

All these issues could be simplified by using a dialog, but thus far pond
avoids them, and I disliket hem myself.
Just slightly better rename for the GUI, still sucks.
Check to make sure another contact doesn't have the same name.
Fix crash when deleting home server message.

Fixes #131.
Just a button
different name
Merge branch 'rename_contacts' of https://github.com/burdges/pond into rename_contacts
Merge branch 'master' of https://github.com/agl/pond into rename_contacts
Merge branch 'rename_contacts' of https://github.com/burdges/pond into rename_contacts
finished code for exposing rename contact functionality to GUI version of Pond