Changes relating to Issue 411
Removed code that was clearing down the segmentation data each
frame.
Added range/parameter checking in vp8_set_roimap(); Return error
if called when cyclic_refresh is enabled.
Correct setup_features() so that it sets or clears the segment update
flags as appropriate.
Change-Id: Ib31ac53006640ddf1ba7b9ec8f8b952e3eff860a
7c32cb52b5