Merge pull request #1 from NullHypothesis/master

Initial import from old SVN repository.
minor changes in probeDirectoryAuthorities function
Changed the way runTests() work, and added a constant for specifying random sleep intervals
Update README.md
Use relative rather than absolute path.

As a result, the user should have ooniprobe in $PATH.
Remove onion routing ports.

In order to test the reachability of directory authorities, only the directory
port is relevant.