getopt for WIN32

getopt files downloaded from GNU C Library 2.18 sources at
http://www.gnu.org/software/libc/
dfu-util and libusbx integration

Modified dfu-util source files for Visual Studio integration purpose.
Added libusbx VS2012 project downloaded from http://libusbx.org and
default path set to C:\SDKs\libusbx-1.0.17
VS2012 integration compilation successfull

dfu-util and libusbx are now integrated to OwlNest.exe
Replace WIN32 by _MSC_VER for better portability
VS2010 integration compilation successful

dfu-util and libusbx are now integrated to OwlNest.exe.
Use of explicit dfu-util global defines.
Default libusbx is set to C:\SDKs\libusbx-1.0.17