Fixes for migrations

Relates to #130, #126.

This PR represents clean work towards fixing migrations after @chartjes [extracted changes to Spot configuration](https://github.com/chartjes/opencfp/pull/130#issuecomment-55760024).

It contains a new base schema dump, updates to README to better instruct on loading, and a naive convenience script for loading schema and running migrations for the first time.

Let me know if you want me to go enumerate some of the tedious diffs between this new base schema and the previous mentioned in #130.  I'm more than happy.