* Added a schema validator.
This allows you to check if the given beau config is valid. Will be used
to improve the CLI and remove schema validation-type errors from the
actual code.
* Added a validate command to the CLI.
This command is a way to test the config file. Eventually it'll probably
be removed and the schema validation will run on every other command. I
have to determine how useful this is and how performance might be
affected.