Added test suite and data.

This PR adds an initial test-suite for the server and adds some test VCF data. The included tests operate by converting the VCF data into wormtable format, and then creating an instance of the `WormtableBackend` for each file. We then verify that the data we get when we run the various API endpoints is what we should see when working directly with the VCF data. This approach should extend easily to the Tabix backend, as we can then create an instance of TabixBackend and reuse all the code to check the values.

Minor changes were made to the existing infrastructure to get and test schemas to allow us to use nosetests and for PEP8 compliance.

To run tests, simply run `nosetests` from the project root.