Change preview size to 640x480 and default values of saturation, contrast and sharpness

I have made a few changes recently - changed the preview size to 640x480 so it should looks better now, and changed the default values of saturation, contrast and sharpness to match the values from the original froyo camera driver. I have also restored the functions I have removed in order to make the camera driver compiling for CM10.1 - I have fixed them rather than removing them.