Add git_tag(sign=False) argument

Tag signing is required for pull requests.  Add the new 'sign' argument
to the git_tag() function.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Add git_push() wrapper function

Signed tags must be pushed to a remote so the maintainer can fetch and
verify them.  Add the git_push() function.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Add --pull-request option

Sending pull requests is a little different from regular patch series.
We need to create a signed tag and push it to the remote.  Then we use
git-request-pull(1) to generate a standard email body.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Add documentation on --pull-request

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Fix incorrect formatting in README.rst

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Add quickstart section to README.rst

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Bump version to 1.0

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Bump version to 1.0+ after release

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>