Added support for NSUUID serialization
Added the ability to override the date formatter in Cerializer

We have had serveral projects where we could not control the date format and had to manually parse it.  Allowing the overriding of the date format will allow users to specify their own date format.
Added common date formatters that have been used in other projects
Merge pull request #2 from shferguson/master

Added support for NSUUID serialization & Custom Date Formatters