[RingtoneThread] fixed crash if no default ringtone is defined

 * This fixes #33.
[VibratorThread] fixed compatibility with api level < 11 (honeycomb)

 * This fixes #34.
[VerifyNumberActivity] make sure editTextPhoneNumber" is shown

 * This fixes #35.
Merge pull request #36 from simlar/compatibility-pullrequest

Compatibility pullrequest