Add support for top-level client-facing project management tool

[tchap]

The idea here is that there would be a top-level client-facing management tool where only user-facing stories would be inserted. The developers would be then creating code-related tasks using GitHub Issues, which would be the then linked to the original ticket in the client-facing tool.

To make the inter-linking step more pleasant and get rid of some manual steps, the daemon could be extended to create these links in case certain keyword/phrase is detected in the body of a GitHub issue. This could be either something like !link <URL> or !parent <URL>. The daemon could parse the URL and immediately know what service it is, e.g. https://www.pivotaltracker.com/n/projects/111111/stories/000000 for Pivotal Tracker, and it could also parse the URL to get all the information it needs to access the service API to create the link in the client-facing tool.

How these links are implemented is service-dependant, e.g. the daemon can create a task for the given story in Pivotal Tracker that is linking the GitHub issue, and the task can be checked when the GitHub issue is closed.