Insert a row for the contact photo if none is found to be updated.

This was already in the original ChameleonOS implementation but I
removed it for some reason.
Add preference to choose background color of identicons
Cleanup
Use PNG images instead of JPEG images.

This allows us to use transparency but will break compatibility with
older versions: contact photos created with previous versions will
not be identified as identicons, which means that using the "Remove
Identicons" option will fail to remove those.
Always set the default icon before loading the actual one in the background
Maintain compatibility with older versions (JPG format instead of PNG.)
Some extra logging
Remove useless check (identicon is never null)
Show notification on errors. Tapping the notification shows the list of errors.
Notify the user if we can't hook the necessary method
Organize strings.xml
Update license headers
Add new style: Gmail like icons (contact's initial on a colored square)
Disable background color pref when Gmail style is selected
Bump version to 1.2