Fix travis
Moved back to a single key class, PublicKey.

- Serialized key is now stored in local db
- UserKey is no more
- KeyFormatter now contains only a utility
  method for formatting key data, it does not implement Key.
Show users QR code on dashboard

- Fix some bugs with rendering in background threads
- Signup process forwards to dashboard when done
Added manual key search option for signing.

- Modify SearchResultActivity to work with startForResult, making it
  re-usable as a generic key search view.
Add initial verification process

- When user has scanned or picked a key to sign, show a verification screen
- User can choose to yay/nay the key
Allow logging out (deletes users selected key and starts over)

- Need to set this up to delete users signed keys and other data as well.