Remove leftovers from RaspiStill.c from camcv.c

This is per the instructions in
http://thinkrpi.wordpress.com/2013/05/22/opencvpi-cam-step-3-create-your-own-project/

I have recompiled the code to verify that it still compiles and works as
expected.
Add version of camcv.c that uses OpenCV

Thanks to Pierre for the sources on this. The new camcv.c takes pictures as a
CV matrix and saves them to foo.jpg.