Added feature for loading and saving camera_info from/to camera flash memory.

I often change my camera's lens, so there is a need to calibrate camera frequently. 
For camera calibration I use camera_calibration ROS package, but it is not handy to create ini or yml calibration file and then load them.
I added feature for saving camera_info data in camera non-volatile memory. With this feature I run only camera_calibration package and it stores camera_info in camera memory.