"Minor" fixes

 - corrected Doxyfile input path
 - added doxygen docs to pack script
 - made unix compile script generate an additional static library
 - Moved __declspec(dllexport) to right place
 - Made WinDOS compile script copy *.a import library to *.lib for
   the MSVC users (tested with MSVC 2010 Express on WinDOS 7, worked!)
Updated README