Add Github Housekeeping Section to README.md

The following Issues are either already fixed by the site redesign, fixed by a pull request by a contributor, or have comments from @rerhar requesting closure:
closes #1
closes #5
closes #17
closes #49
closes #56
closes #62
closes #101
closes #109
closes #111
closes #142
closes #180
closes #181
closes #195
closes #199
closes #214
closes #221