Support different types of post-receive hooks

- [x] `push` - Any git push to a Repository (commits, branches and tags are fully supported)
- [x] `issues` - Any time an Issue is opened or closed.
- [x] `issue_comment` - Any time an Issue is commented on.
- [ ] `commit_comment` - Any time a Commit is commented on.
- [x] `pull_request` - Any time a Pull Request is opened, closed, or synchronized (updated due to a new push in the branch that the pull request is tracking).
- [ ] `pull_request_review` - Any time a Pull Request Review is acted upon.
- [ ] `pull_request_review_comment` - Any time a Commit is commented on while inside a Pull Request review (the Files Changed tab).
- [x] `gollum` - Any time a Wiki page is updated.
- [ ] `watch` - Any time a User stars the Repository.
- [ ] `download` - Any time a Download is added to the Repository.
- [ ] `fork` - Any time a Repository is forked.
- [ ] `fork_apply` - Any time a patch is applied to the Repository from the Fork Queue.
- [ ] `member` - Any time a User is added as a collaborator to a non-Organization Repository.
- [ ] `public` - Any time a Repository changes from private to public.
- [ ] `team_add` - Any time a team is added or modified on a Repository.
- [x] `release` - Any time a release is published
- [x] `status` - Any time a Repository has a status update from the API
- [ ] `page_build` - Any time a Pages site is built or results in a failed build.
- [x] `ping` - Any time a new Github hook is created
- [ ] `create` - Represents a created repository, branch, or tag.
- [ ] `delete` - Represents a deleted branch or tag.
- [ ] `deployment` - Represents a deployment.
- [ ] `deployment_status` - Represents a deployment status.
- [ ] `label` - Any time a label is edited

supybot-github also supports the following third-party services:
- [x] [Travis](https://travis-ci.org/)
- [x] [AppVeyor](https://www.appveyor.com/)

No source file, test, or entry point is named in the issue. Start by locating the webhook handling code and comparing its existing event support with the unchecked GitHub hook types; done means the selected hook types are handled consistently and covered by appropriate tests.

Written by the indexing model from the issue text.