Various camera fixes

Sometimes camMode is left on when switching from video to still mode.
Detect the switch and allow it to be reset.

Do not set camMode on rear camera (yet).

preview fixes for ApexQ

Change-Id: I1ff0153ccb402e0e67e1660210829f07a90dee7a
d2lte: fix Skype video chat

Change-Id: Ife14f9c54b0cd77457fc8a76597d73ab870df947