Eleven: some perf improvements mainly when interacting with the widget

The main culprit is passing large default artwork to the remote views
It also appears that the events from the service may fire multiple times but
fixing that is not a small change - for now cache some of the heavier operations
instead

https://cyanogen.atlassian.net/browse/MUSIC-120

Change-Id: I8bbb10357c9d7d1c01ef5e7627efdf8e9b956421