bin/map: Use the same XML tree for each row in DB outputs, to eliminate time spent creating the tree from the XPaths for each row

bin/map: map_table(): Resolve each prefix into a separate mapping, which is collision-eliminated, instead of resolving values from multiple prefixes when each individual row is mapped

bin/map: Moved collision-prevention code to map_rows() so it would only run if there were mappings, and so that it would run after any mappings preprocessing by map_table() that creates more collisions

bin/map: Prevent collisions if multiple inputs mapping to same output

mappings/DwC1-DwC2.specimens.csv: Mapped collectorNumber and recordNumber to recordNumber with _alt so they wouldn't collide when every input column, even empty ones, are created in the XML tree

bin/map: If out_is_db, in debug mode, print each row's XML tree and each value that it's putting

bin/map: If out_is_db, in debug mode, print the template XML tree used to insert a sample row into the DB

bin/map: map_table(): When translating mappings to column indexes, use appends to a new list instead of deletions from an existing list to simplify the algorithm

union: Omit mappings that are mapped to in the input map, in addition to mappings that were overridden. This prevents multiple outputs being created for both the renamed and original mappings, causing duplicate output nodes when one XML tree is used for all rows.

union: Omit mappings that are mapped to in the input map, in addition to mappings that were overridden. This prevents multiple outputs being created for both the renamed and original mappings, causing duplicate output nodes when one XML tree is used for all rows.