Issue #83 Updated record_string to correctly escape quotes and backslashes 

...when turning the datashape into a string.

This fixes a problem in blaze where converting from one datatype to another would throw errors when transferring the datashape from one source of data to another.
Several tests have been added and all tests pass.
I think it would be better to invert this logic, to check whether it matches the specific grammar of an identifier name. I think that regex would be ``[a-zA-Z_][a-zA-Z0-9_]*``. Should also add tests that exercise the edge cases here (starting with a number, unicode characters, etc).