Re-issue of change which adds two-finger touch look to avatar.
The option is un-checked by default because of an unsolved problem: We're getting the events into Qt very slowly, so input from several seconds ago is still active when the user has stopped the touch action. This needs to be fixed before this can be turned on full-time.
Corrections were made per feedback, and the change has been merged with the latest.
Merge pull request #570 from machinelevel/master_central

Re-issue of change which adds two-finger touch look to avatar.