Support cross-compiling for win32.
Support cross-compiling for win32.

The stdlib os/user depends on cgo which means you can't cross-compile
for win32 from darwin. Using mitchellh/go-homedir provides a pure go way
  to get the homedir.

thomaso-mirodin/go-shorten,thomaso-mirodin/go-shorten,didip/shawty,thomaso-mirodin/go-shorten