schemas/VegCore/VegCore.ERD.mwb: added labels for GNRS and geovalidation steps, analogous to the TNRS taxonomic scrubbing steps labels

schemas/VegCore/VegCore.ERD.mwb: regenerated exports. VegCore.ERD.png now gets the sRGB color profile attached in Gimp so that the colors don't look washed out on some LCD screens.

schemas/VegCore/VegCore.ERD.mwb: georeferencing: added hstore extender

schemas/VegCore/VegCore.ERD.mwb: individual: made it a plot element by optionally attaching a plot position (a rel_place whose parent is the containing plot)

schemas/VegCore/VegCore.ERD.mwb: plot: replaced bounding_box_rect with length_m, width_m, since the bounding box was intended to store plot dimensions (along the plot azimuth) rather than an actual bounding box aligned to the compass directions. added azimuth_deg_N, which is used to resolve plot element x/y coordinates to absolute geocoordinates while taking into account the rotation of the plot.

schemas/VegCore/VegCore.ERD.mwb: tables with parent hierarchies: made parent optional, since the root(s) of the hierarchy will not have an entry for this, and any unique constraints that include this column should be ignored (which they will be if the value is NULL instead of a self-pointer)

schemas/VegCore/VegCore.ERD.mwb: subplot: renamed to rel_place and inherit from place directly, in order to store other plot elements that are relative to their containing plot

schemas/VegCore/VegCore.ERD.mwb: taxon_path: converted to an auxiliary table of taxon_name instead of a subclass of it (like geopath for the place table). this causes distinct taxon_paths to be stored only once, instead of repeatedly for each taxon_name.

schemas/VegCore/VegCore.ERD.mwb: place hierarchy: reorganized to store scrubbed geoplaces in a containment hierarchy instead of a denormalized geopath. this allows each source-specific place to be GNRS-scrubbed to a GADM place, and then have its coordinates geovalidated to see if it is within the matched GADM place. this uses the georeferencing table to store the matched GADM place (scrubbed_geoplace) for each input place, instead of geopath_scrub to store the matched GADM geo*path* for each input geo*path*. (this avoids the need to scrub every combination of place ranks, because just the name of each place is scrubbed relative to its parent place.) geopath instead becomes an auxiliary table to store the place table's verbatim ranks, for easy access and storage.

inputs/SpeciesLink/Specimen/map.csv: conceptual_darwin_2003_1_0_BoundingBox: remapped to UNUSED