Feature: database diffing / sorting

[klauer]

Expected Behavior

It'd be nice to take a look at a pull request of auto-generated database files and compare what has really changed.

Sometimes diff algorithms mess things up, sometimes the auto-generated tools write things in a different order, etc, but whatrecord could do a better job of saying this record.field changed from a to b.

Maybe: whatrecord db --diff to diff two databases
Maybe also: whatrecord db --sort dbname to sort records in place