Load Maryland 2000 results to RawResult

Account for results reported as county portion of congressional
district.

Addresses #49
Better recording of results recorded by congressional district split by county

I'm pretty sure this only applies to results for the presidential
primaries.  Make sure the reporting_level is set to
"congressional_district_by_county".

Ignore these in the main transform because we'll want to aggregate
these up into a single Result per district/county.

Addresses #49, #80
Handle case where string is already unicode

Support running ocd_type_id() on text that is already a
unicode object.
Create Contest, Candidate and Result records for 2000 primary

Addresses #49