vendor snappy

cc @andybons @petermattis @spencerkimball @tschottdorf 
ok. I can leave it off. Preference I guess. I usually like to see a single line for building large sub-parts when building all from top level and then just spewing errors if any. This goes well if you can also specify a --verbose. I gravitated to this from how the plan9 from user port sets up its mk builds.