Look at JSON descriptor to determine datatype

Socrata is now picky about datatypes in some cases. Code was modified to always surround non-numeric values with tics, but that doesn't always work.

Consider a way to reference the datatype for an attribute from Socrata data descriptor.

This could be done proactively or on failure.

Down the road consider caching results so these fetches don't need to be repeated if the getting and analysis of them is expensive.