Closing in on having the OData data source working

I rearranged some things today to make the code easier to read.
Notably:
The search params are now broken out into their own files.
There's now a Data.OData and Data.SQL namespace.  (SQL is presently
empty)
The composing the operand strings now requires the operator so that we
handle any formatting that is sensitive to the context.

The OData source appears to now be "working," but crashes because I
can't make it search for anything that doesn't come back with a
gazillion hits yet.