If the contact doesn't have an image, render a color-coded
background and the first letter of the contact's name.
1) Don't display anything during recipient resolution.
2) Display a # icon in material gray for recipients with no name.
3) Display a material group icon in material gray for groups with
no avatar icon set.
Closes#3104
// FREEBIE
* unify single and multi contact selection activities
* follow android listview design recommendations more closely
* add contact photos to selection
* change indicator for push to be more obvious
* cache circle-cropped bitmaps
* dedupe numbers when contact has multiple of same phone number
// FREEBIE
