CONTRIBUTING.md: List myself as maintainer for everything :p

I'll never have time for this, but it's a start until we get other
volunteers ;).  Please, take these away from me!
Merge branch 'restructured-version-control' into restructured

* restructured-version-control:
  version-control/git/README.md: Add paragraph pitching Git
  version-control/README.md: Add a motivational paragraph
  version-control/git: Use git-and-github notes
  version-control/svn/cheet-sheet.md: Add a Subversion-specific cheat sheet
  version-control/git/cheet-sheet.md: Add a Git-specific cheat sheet
  version-control/cheet-sheet.md: Add a generic outline for the cheat sheet
  version-control: Make README.md and instructor.md more generic
  version-control: Add README.md and instructor.md from the guide
Merge branch 'restructured-testing-nose' into restructured

* restructured-testing-nose:
  testing: More restructuring for the Nose source
  testing/cheat-sheet.md: Split Nose-specific stuff into nose/cheat-sheet.md
  testing/nose: Restructure to split out examples
  testing/nose: Move example scripts into the examples/ subdirectory
  testing/nose: Move media into the media/ subdirectory
  testing/nose: Move existing Nose material to $SUBJECT/$TOOL