Initial working version

This first version supports publishing images from the top
camera on Nao. No configurability yet.
Added support for dynamic reconfiguration of all Nao v4 camera params

Only reconfiguration of FPS, resolution, and source requires restart
of the driver.

Also, correctly unsubscribe/release from the video proxy.
Use the Nao TF frames + generate unique calibration files

Make sure we generate calibration files different for each resolution/camera
Support only RGB8 colorspace

If BGR is useful to someone, we can re-introduce it. For now, keep
things simple.
No easy way to go 'local'

From a performance point of view, it would be very beneficial to be a
NAOqi 'local module' to access the video buffer.

It remains to be seen if we can write a ROS nodes that also happen to be a
NAOqi local module (that would allow much better performances for the camera
node).
Only publish frames when someone is listening on the topic

This saves a lot of CPU on Nao when images are not needed.
Remove useless mutex
Cosmetic refactoring