git remote: "origin" is not always the remote

Adding a top level flag for `pulls` and `issues` to specify an alternate
git remote (default is still "origin"). This took a little rearranging
of the Manager code, to be inside the app.Action (so the flags are
parsed at that point).

Now you can `pulls --remote crosbymichael` to see those instead of the
dotcloud list.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
remotes: process the manager in the Before context

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
My localhost does not have go installed - give me a Dockerfile
add username support in --maintainer
issues: include a command to close an issue

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
gofmt -s -w .

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Merge pull request #128 from vbatts/vbatts-remote_flag
Propagate error back to caller.

Docker-DCO-1.1-Signed-off-by: Rohit Jnagal <jnagal@google.com> (github: rjnagal)
Merge pull request #134 from rjnagal/master

Propagate error back to caller.
Merge pull request #131 from dotcloud/add_username_maintainer

add username support in --maintainer
add --milestone to issues
display milestone in list
Merge pull request #132 from dotcloud/issues_milestone

add --milestone to issues
issues close: update the usage/description

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Merge pull request #133 from vbatts/vbatts-issues_close

issues: include a command to close an issue
github.com/dotcloud/gordon -> github.com/docker/gordon
Merge pull request #135 from docker/update_pkg_path

github.com/dotcloud/gordon -> github.com/docker/gordon
Gordon should return errors, not silently fail. Fixes #136
Merge pull request #137 from fkautz/fix-error-code

Gordon should return errors, not silently fail. Fixes #136
upate docker path