GitlabUpdate: use stripped path for repo_name
Use a default for gitlab_url that usually works
Mention Unicorn on a domain socket as an exception
Improve coverage.
Use simplecov for development.
Merge branch 'working_gitlab_url' into 'master'

Use a default for gitlab_url that usually works

This default lets gitlab-shell connect to Unicorn directly, instead of
going through Nginx. This has the following benefits:

- the majority of users no longer has to edit the `gitlab_url`;
- avoid issues when the external GitLab web address does not resolve on
  the GitLab server itself;
- avoid SSL certificate issues.

See merge request !32
Merge pull request #158 from Aigeruth/improvement/coverage

Improve coverage.
Merge branch 'master' of github.com:gitlabhq/gitlab-shell
Merge pull request #155 from ssandler/master

GitlabUpdate: use stripped path for repo_name
Merge pull request #159 from Aigeruth/improvement/simplecov

Use simplecov for development.
Fix tests
Update CHANGELOG

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>