Previously, weird math was used to determine which column should be pulled from the PRMS nhru file.  In this update, the nhru column index is written directly into the userData hash that is stored with each attribute definition.  When a attribute value is read, we look for a userData entry for "NHRU_FILE_ATTRIB_COLUMN" and if its present, we know that the column comes from the nhru file and we know which column to look up.
Also added logging.
Merge pull request #19 from USGS-CIDA/FieldIndexedDbaseFileReader_bug_fix_for_skipping_last_value_in_dbf

Previously, weird math was used to determine which column should be pull...