This is to address a bug(?) found during the attempt to integrate with Crichton.  For some reason representor_builder needed representor_hash to be required.  Identical use is foudn in the builder spec without reproing the error - I cn only find the error when referencing it through Crichton, so I'm not sure how to confirm the test.  Also the behavior seems strange since /lib/representors 'requires' all the files and they are in the same module, so this behavior seems inexplicable to me.
Merge pull request #39 from mdsol/representor_hash_reference_bug

This is to address a bug (?)