bin/my2pg: added instructions for regenerating *.schema.sql whenever this script is changed

bin/my2pg: COMMENT: also match COMMENTs with embedded ', because there will only be one COMMENT per line, so the contents of the COMMENT can just extend to the last ' on the line

bugfix: lib/sh/util.sh: $sed_cmd: make output unbuffered, so that running e.g. bin/my2pg at the command line produces output as each line is read

bin/my2pg: replace MySQL ` quotes with " quotes to support exports that were generated without ANSI_QUOTES mode. (this replacement only applies to schema exports, not data.) ANSI_QUOTES is only available with mysqldump --compatible modes that also include NO_TABLE_OPTIONS, which omits important table options such as comments. in particular, these comments are part of schemas/VegCore/VegCore.ERD.mwb but were not being included in VegCore.my.sql.

schemas/VegCore/VegCore.ERD.mwb: taxon_string: removed parsed_taxon_assertion field, since there may be more than one parsing (TNRS result) for a given taxon_string. the parsing relationship can better be represented by adding a parsed_taxon_assertion whose taxon_assertion.string points to the parsed taxon_string. getting the parsed_taxon_assertion for a taxon_string now requires joining on parsed_taxon_assertion using a backwards instead of forwards fkey, and filtering the corresponding assertions to include only the ones for TNRS (of the desired TNRS version). documented that taxon_assertion.string was previously the concatenated matched name, but is now the TNRS input name. the concatenated matched name is still in parsed_taxon_assertion.matched_taxon_concept->:taxon_name.unique_name.

schemas/VegCore/VegCore.my.sql: regenerated from .mwb schema, which apparently reverses the order of the fkeys (possibly a Linux MySQL bug?)

inputs/SpeciesLink/Specimen/map.csv: remapped Darwin Core synonyms to DUPLICATE. this avoids the need to translate these to postprocessing derived columns for new-style import, and also speeds up column-based import because there are less automatic alts to perform to resolve filter-less collisions. the svn diff was verified by replacing DUPLICATE#of:dwc_terms<term>#... with <term>, removing the comment, and checking that this removes the diff (except where VegCore has renamed a DwC term).

bugfix: inputs/SpeciesLink/Specimen/map.csv: *scientificName: remapped to scientificName instead of taxonName to match the DwC term's name (this is the same dwc_terms_scientificName mismapping that was fixed in r10434)

bugfix: inputs/SpeciesLink/Specimen/map.csv: dwc_terms_scientificName: remapped to scientificName instead of taxonName to match that DwC term name, as well as the mappings of other *scientificName terms

inputs/SpeciesLink/Specimen/map.csv: marked dwc_geospatial_VerbatimLatitude,Longitude as exact duplicates of dwc_terms_*