Move docker build to client
Add "Cmd" prefix to builder instructions
Make sure to have a command to execute upon commit
Isolate run() from commit
Tag all images after pulling them
Make docker client an interface
Allow multiple syntaxes for CMD
Merge fix
Use pointers for the object methods
Fix an issue trying to pull specific tag
Merge pull request #653 from dotcloud/builder_client

* Builder: Move the Builder to the client
Update docker builder doc
Remove no longer needed tests
Merge pull request #658 from dotcloud/builder_client_doc

Builder client doc