Add Godeps file to make note of a good working configuration.

Using godep is not necessary (in fact, you might potentially build an
older version with fewer bug fixes/improvements), since I plan on
keeping gostatus working with its dependencies at tip. However, I'm
gonna add this now for reference, just in case something
unintentionally breaks.
If gostatus doesn't build with tip dependencies, then use this Godeps
file and please open an issue so I can fix it.