Camera: Skip switch camera command when camera state is busy

Check camera state before execute switch camera command to avoid
camera issue.

CRs-fixed: 552026

Change-Id: I301f2a135ba873b1370d709d1251f88711bac8cb
Camera: use send command to main handler to avoid race condition

It will met race condition when switch from panorama to video
and then press capture button quickly. Use send command to enable
shutter button to avoid race condition issue.

Change-Id: I3d6e299fb84a9ab9b323b00bff2f8a3cb8ca3df4
CRs-fixed: 545612
Gallery2: not enable video pause feature for Timelapse recording

Current design do not support video pause for timelapse recording,
so disable this feature for timelapse recording.

Change-Id: Ib5dd90569c52f9db41988384f2a58ed789c87c49