Godeps: update go-dockerclient
Makefile: simplify file

Delete some old files, allow the use of extra flags for Go (we will use
-x in travis, see #866).

Since we no longe expect to run our tests on go < 1.2, we're safe to use
go get -t instead of combining go list + xargs go get.

I'd love to get rid of this file, but I don't think we can do it right
now.
travis: pass -x to make get and make test

Also removed the call to travis_test. Running just make test is enough
here.

This is supposed to solve #866 (I hope github doesn't close this issue
automatically).
Makefile: actually run go test -race

-i will just install the dependencies.
safe: add Writer

Writer is a safe writer :)
safe: add race test to ensure Writer's safety
safe: rename Reader to BytesReader
safe: add Reader
safe: add race test to ensure that Reader is safe
fs/testing: fix api for safe.BytesReader
provision/docker: use safe.Writer and safe.Reader in shell

Fixing a data race with the streams.
safe: fix year in copyright headers