Added a libfreenect2_api export macro - to apply __declspec(dllexport) infront of all classes that is used from the library libfreenect2.

If they are not specified VS won't generate a .lib file and protonect will give linking errors.
to use max in VS <algorithm> needs to be included and <type> as to be used.
Added FindLibUsb and FindTurboJPEG cmake files, to search for the respective libraries, instead of hardcoding in a sub depend folder.

Only testet on windows.
Made a ifdef for packing data to work on windows also.
Added header files so they are visible in VS solution tree.