#229: testing: caching git now uses 'which git' to get path to git instead of hard-coded /usr/local/bin/git
#229: CONTRIBUTING.md was updated
Merge pull request #239 from yeputons/issue-229

Issue 229: Don't force `/usr/local/bin/git` for tests
Merge branch 'master' into windows-updates

Conflicts:
	spec/acceptance/test_spec.js
Refactored how we get the windows vs linux paths, this approach makes windows consistent in both cygwin and cmd.
Changed the mrt.js call to use the meteorite.cmd file created by 'npm install'. This fixed 38 tests for me.
 - TODO: Refactor how we get the paths for tests, fix the 3 remaining tests and clean up a few odds and ends.