Implemented better handling of the value input of FWGS. It now takes the string 'all_values' which creates a WFS query that returns all values. I don't think we want the default behavior to be all values, so this should be a good solution.
Implemented a couple tests for the _getFeatureCollectionGeoType function.
Merge pull request #36 from dblodgett-usgs/master

Fixed up shapefile attribue value handling.