Add tests for the Aa dialect’s semantic wiki-links

The test that does not pass now is wikifying links, sherry turkle -> Sherry_turkle
The tests that are not implemented yet are for filters and presentation modes,
because the syntax is not really defined yet.

To run the tests, first:

    npm install

Then:

    npm test
Merge pull request #1 from codingisacopingstrategy/aa

Add tests for the Aa dialect’s semantic wiki-links