Catch and fix (somehow) common configuration errors

If a user makes a common mistake in his or her config file, we should be nice
enough to catch it and print an error message. An example of this is when
`paginate` is set to `true`. As @benbalter points out, a user will see

> error: undefined method to_i' for true:TrueClass

This isn't helpful very helpful so if as we find them over time, it might be
nice to catch them and be more helpful instead of frustrating.

Related to #1105.