Basic implementation:

* Windows support - need to expand API provided by MTP_DLL.dll
* OS X support - need to statically link against libusb and libmtp
* Load bootloader.bin from a file

Ideas for future features:

* Dual-boot.  Look for nk.bin in current directory, and check its
  md5sum to confirm it's an original firmware.  Possibly include
  override for user-modified OFs, and option for user to specify an
  alternate location.  

  This will give the user three options - rockbox only, OF only
  (i.e. uninstall) or dual-boot.  It would be easy to give the choice
  of two boot orders (RB on hold or OF on hold) if that was desired.

