Add signal to KillContainer

Comes from
Issue: https://github.com/dotcloud/docker/issues/4549
PR: https://github.com/dotcloud/docker/pull/4576
Merge pull request #91 from jefferai/master

Support the API option to force removal of a container
authors: add Jeff Mitchel
authors: add Cezar Sa Epinola
Fix CommitContainer & Config

Fix CommitContainer to send the container configuration as the HTTP request body.

Fixes issue 78
authors: add Andy Goldstein
Update client.go

Don't log empty status lines.
authors: add Simon Menke
Merge branch 'add_signal_to_kill_container' of github.com:Soulou/go-dockerclient
container: add options to KillContainer
authors: add Soulou
container: remove useless fmt.Sprintf call

Really?
container: remove unnecessary tag definition for struct field
container: provide some constants for signals on KillContainer
Set TAG during an image import
authors: add Salvador Gironès
buildImage accepts remote dockerfile
Merge branch 'master' of github.com:fsouza/go-dockerclient
add test to buildImage with remote dockerfile
gofmt