Modal presentation of the setup view.

- Memory efficiency.
- Fixes issue where segues were never unwinded.
- Fixes issues on first launch where initiating a call would show the login screen again.
- Addresses issue where the signup code would not have been added properly after clicking link in SMS.

Reviewed by: @FredericJacobs
Multiple UI enhancements.

- Addresses consistency in how phone numbers are displayed.
- Auto-Layout constraints for Settings

Review by: @FredericJacobs
Support for Archiving. (Closes #213)
Immediate feedback on send + unread count badges.
Signup flow: request call.

• enables the "Send Again button"
• enables the display of the number the user entered in the Registration View in this subsequent scene (so they can see whether they should go back or not)
• enables the "call me instead button"

Reviewed-by: @FredericJacobs
merge