Add help screen to explain Silent Manager.

version 1.7

1- Adding new screen for multi-picker contacts

2- Solving problems with hidden contacts like Facebook and contacts without phone numbers

version 1.8

Add google analyitics to improve user experience

Fix bugs

version 1.8.1

Fix bugs

Add messages to help user

version 2.0

Support for contact custom ring tone.

version 2.0.1

Fix bug appear on some versions

version 2.1.1

Fix kitkat bug for external ring tone.