implement everything in Go

[Cryptophobia]

From @smothiki on March 8, 2016 23:42

because of beta crunch time we haven;t explored enough options to use a go cli based client to build docker images and PUSH to remote registry.
Also moving a head in the future we have to support multiple object storage backends.
Also add support to talk to remote docker deamon along with mounting docker socker

Copied from original issue: deis/dockerbuilder#31

[Cryptophobia]

From @mboersma on May 19, 2016 19:59

This would be a nice refactoring, and @smothiki thinks it is possible now that Docker's cli interface may not be locked to a specific release. But it's not happening for the Workflow 2.0 release so I'm removing this milestone.