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.
can you give the tests more descriptive names? we should be able to at least have a general idea of what the test is testing without having to read the source.