Improved the phone number editing during registration

Please do manual testing on an actual iphone, as I could only try in the simulator.

- Fixed a crash where an offset wrapped around when deleting the opening bracket
- Backspacing now skips over formatting characters
- Cursor position is maintained more accurately when reformatting
- Added a few utility methods
- Also fixed a test not having "test" as a prefix, causing it not to run
FREEBIE