xml_func.py: _eq(): Documented that '' (empty node) is returned if a value was not mapped to, not if a value was None, since None arguments are no longer removed by process() (now XML functions do this manually with conv_items())

xml_func.py: _ref(): Only display "XPath reference target missing" warning if target node does not exist, not if it exists but is empty

xpath.py: get(): reference expansion: Use get_1() and check for None result instead of using get(), which returns multiple nodes when we just want the first

mappings/VegX-VegBIEN.stems.csv: Reversed XPaths so that they start with location instead of plantobservation

lib/common.Makefile: Added $(cp)

mappings/Makefile: Include lib/common.Makefile

lib/common.Makefile: Added $(CP)

inputs/import.stats.xls: Updated with stats from latest import

mappings/VegX-VegBIEN.stems.csv: Reversed input XPaths so that they start with plot instead of individualOrganismObservation as stem

inputs/CTFS: Disabled maps because CTFS is not yet compatible with reversed XPaths, but the effort required to make it compatible is not worth including in the current commit. We lose only 2 test rows of test VegX data by doing this, since the full CTFS VegX files were never able to be imported.