xml_func.py: _date: month: Convert month names to numbers before casting everything to int

xml_func.py: _date: Refactored to convert items to dict right away, and use iteritems() for later type conversion. This will enable month names to be converted before casting everything to int.

mappings/Makefile: Sort mappings/DwC.self.specimens.csv so that entries can more easily be found when using it as a DwC terms reference

Added inputs/UNCC

Added inputs/U/test with accepted test outputs

inputs/U/maps/DwC.specimens.csv: Mapped most of the remaining fields

input.Makefile: Clean up via maps when they change by subtracting the via format's self map from the via map (the comments column is ignored in determining which entries are redundant, and empty entries with a matching input column are also removed)

subtract: Fixed bug where entries were removed even if maps were not combinable and ignore was off

union: Fixed bug where combinable was not saved for use in deciding whether to add entries in map 1 that weren't already defined

inputs/U/maps: Set svn props