libbladeRF: Added API_EXPORT for API routines.
Updated async test

Updated to be able to compile with VS2012.  Untested, and probably won't
work correctly.
Added pthreads-win32, and getopt/getopt_long to Windows build.
bladeRF-cli: Fixed struct field initializers and removed use of unistd.h
bladeRF-cli: Fixed pthreads-win32 linking issue