Mms: Use the nice colorful LetterTileDefaultImages

Use the new default contact images introduced in Android 4.4.3

PS12:
-added missing mContactKey init

PS13:
-added for more avatar calls

PS14:
-whitespace

PS18;
-quick message popup

PS19:
-fix contacts caching in recipients picker
-fix derp in dividers

Change-Id: I280a5e3abb8dffb9340d360a99da966ea48746f1