introduce top-level Makefile to build the docker binary
add a test target
use .gopath/ instead of build/
do not print executed commands
slightly re-phrase the build from source in README
allow for verbose output from go tools
print the location of the built binary
Merged branch sa2ajj/top-level-makefile
vagrant: Simplify provisioning to build from repo

This sets up an idiomatic Go workspace in /opt/go with the source
shared from the host directory in
/opt/go/src/github.com/dotcloud/docker and docker installed into
/opt/go
Merge pull request #184 from titanous/simplify-vagrant

vagrant: Simplify provisioning to build from repo
Merge remote-tracking branch 'upstream/master'