Add more thorough tests

[greduan]

This is just a nice thing to do.

Add a test for every setting, just to make sure that it works correctly and without any errors or incorrect parsing.

Of course not necessary, but more like a best practices. Make the tests as thorough as possible. :)

Check my test case for what I mean: https://github.com/Greduan/docpad-plugin-textile/tree/master/test

It's only one file but it covers a lot of what Textile would parse. :)

[RobLoach]

Thanks a lot for the guidance, I really appreciate it! I'm always a fan of more tests.