Always send revocations to the home server
Start of command line interface
Populate the contacts UI later.

Previously, if you created a contact but clicked away before picking the key
exchange mechanism, Pond would crash because the pending contact didn't
have enough fields setup at that point.

This change delays populating the state and UI until either manual
keying has been selected, or the PANDA has been started. (Previously,
clicking away after selecting shared-key exchange and clicking back
would result in the manual key exchange UI!).
Make user click Revoke button twice.
Fix up any state files with bad revocations.