Added resetMode method, applied GNU-style to all project

- this method is intended to be called to reset camera mode state
to its initial value (it does not switch mode but just reset state
variable)
Added switchToMode method, added a pause after call to switchToNextMode

- the switchToMode method allow to switch to any of the camera modes
- declared a constant SWITCH_MODE_PAUSE_MILLIS in FCOEV2.h, representing
the delay in
 milliseconds to wait after calling switchToNextMode in order
to be sure that camera has correctly process the order
- added a SWITCH_MODE_PAUSE_MILLIS delay at the end of switchToNextMode