Fix chaining order in gst_omx_camera_src_change_state()
Don't implement get_times(), not really needed for a true live source
Consistently use the object structure for GstVideoInfo stuff

Also declare dependency in gst_omx_camera_src_decide_allocation() on
gst_omx_camera_src_set_caps().
Better color enhancement configuration

Use two separate integer properties for color enhancement configuration
U and V channel values.
Simplify device start/open, close/stop and start/stop capture chains

Move functionality of the separate open/close functions directly in the
start/stop GstBaseSrc virtual functions. Also combine functions
enable/start and stop/disable handling video capturing.
Use an array of pointers for components and ports in the object structure
Don't try to deallocate buffers of a port if port is tunneled

gst_omx_component_free() was calling gst_omx_port_deallocate_buffers() on
each port of the component's ports without first checking if the port is
tunneled or not. Only buffers for non-tunneled ports should be
deallocated as the system is handling resource allocation and
deallocation for tunneled ports. This would fail if a component has
both tunneled and non-tunneled port, resulting an assertion being thrown
in gst_omx_port_allocate_buffers_unlocked().
Tunnel camera preview output port to null sink input port in Raspberry Pi

According to [1] using preview port contributes to the data used by
algorithms controlling the camera. So lets open and use the preview port
but discard the images by sending these to the null sink component.

[1] http://www.raspberrypi.org/wp-content/uploads/2013/07/RaspiCam-Documentation.pdf