Add self-test suite. WIP.

At the moment, when running 'test.sh' from (and in) the 'tests' directory, Selenium webdriver is downloaded and runs a simple hello world test (with one failing assertion).

Also includes my mocha testsuite from froh42's ``multi''. This is non-functional without the site. See https://github.com/froh42/multi/tree/master/selenium.

Maybe having a dependency like "Mocha" is too fat for a self-test suite; But maybe, also, including some framework that gives an idea how to use this thing is in order. Will meditate on this some more.

Also, the scripts are all copied from ``multi'', many thanks to froh42 and jmbreuer, who have written most of this and who I know personally to be the most awesome folks.