Support numeric and textual data types

This allows querying CloudSearch 'uint' data types. Right now, if you try to do an equality or an inequality comparison with a 'uint' data type, Cloudsearchable wraps the clause's value in single quotes. The server rejects this as not being compatible with a uint type. This patch wraps clause values in single quotes only if they're not integers.

Additionally, I refactored the unit tests a little bit.