C++ cscore classes should be in their own headers

[calcmogul]

Currently, all the classes are thrown into a handful of aggregate headers.

• cscore.h
• cscore_cpp.h
• cscore_oo.h
• cscore_raw.h
• cscore_c.h
• cscore_cv.h
• cscore_raw_cv.h

This violates include-what-you-use, and it's not clear which header contains what (e.g., the MjpegServer, UsbCamera, or HttpCamera classes). Java gives each class its own file, mainly because the language requires it.