- also remove analytics beacon in README, which is not that useful
  anymore.

- all of Spack is Apache-2.0/MIT
- no packages are LGPL-2.1

This updates Spack's top-level metadata files to reflect the new
Apache-2.0 and MIT licenses.

- This isn't one of those autogenerated SVGs from a drawing program!

- This is a completely re-traced, minimalist SVG file with clearly
  delineated pieces so that your favorite renderer can draw a Spack logo
  at whatever resolution you want.

- Included versions with text, as well.

We moved to a new GitHub org! Now make the code and docs reflect that.

- Added a badge to show who's online.
- Added a section under "Get involved!"

- Update version guard in spack script to allow python 3
- Update min required version in the docs

* Switch from coveralls to codecov

- Add .codecov.yml, simplify .travis.yml
- Add codecov badge to README.md

* Add tests for spack graph.

* Major updates to Contribution Guide

* Grammar changes

* Fix missing/extra backticks

* Rewording, links, and tips added

- Docs are now visible immediately, and we don't have to push them
  separately.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>