Allow spaces in field names.

...  Somewhat less efficient to have to fetch all the fields in the
doc, but to be able to use fields containing spaces, this seems to be
necessary... I suppose we could do this conditionally--only if one of
the fields we're looking for contains a space... meh.
Merge pull request #18 from adam-vessey/7.x-UMKC-7

Allow spaces in field names.