Gallery now remember previous album selection.

Also defaults to the camera roll album the first time the gallery is used. Also handles albums being deleted or renamed since the app was last in the foreground.

Change-Id: I32c5b3248dc482292fb77821b5c926186c091525
Found and fixed a crashing bug related to failed download requests.

Change-Id: Ic5aad9e0e97e3809e20700065efc1e09556195d2
Merge "Gallery now remember previous album selection."