Redesign of registration process.

1) Added a country selector and as-you-type number formatting.

2) Split out the registration progress into a separate "modal"
   activity that explains what is happening and gives deterministic
   progress.

3) Put the logic into a service, with the Activity serving as a view
   for the service, which should allow users to change focus without
   any adverse effects.

4) Redesigned the look to be hopefully less ugly.

5) Allow processing in background, with a notification on error/success
   if the registration activity is not in focus.
Be sure to finish activity, and don't mess with keepalives.
Fix for state management issues with registration flow.
Touch up the new registration process.

1) Change language introducing the registration process.

2) Refactoring based on SOA feedback + class-level comments.

3) Added confirmation dialog before launching verification.
Merge pull request #78 from WhisperSystems/registration

Redesign of registration process.