Added multiple new event types to the github_activity.js library.
These include:
- CreateEvent
- DeleteEvent
- ForkEvent
- PullRequestEvent
- IssueCommentEvent
- WatchEvent (starring a repository)
- MemberEvent (adding a member to a repository)
Added the branch name to the PullEvent as well.
Minor styling updates to index.html as well as additions to README.md.
Updated README.md file with information about embedding the activity widget.