schemas/vegbien.sql: locationevent: added stratum_id to unique constraints, so that there can be multiple locationevents for the same underlying event but with different strata

schemas/vegbien.sql: link locationevent to stratum instead of the other way around (similar to how it's represented in normalized VegCore as stratum_event->stratum, rather than stratum->taxa_sampling_event). this works around column-based import's lack of support for linking two tables together via two separate routes (in this case locationevent->taxonoccurrence->stratum and locationevent->stratum).

web/links/index.htm: updated to Firefox bookmarks. added PostgreSQL links.

schemas/vegbien.sql: stratum: added stratumname

mappings/VegCore.htm: regenerated from wiki. added Stratum table.

schemas/vegbien.ERD.mwb: updated to PostgreSQL schema

schemas/VegCore/VegCore.ERD.mwb: model options: template for new fkey names: use the PostgreSQL naming convention so that new fkeys will sync properly with equivalent fkeys in the Postgres schema that have had their names reset

schemas/VegCore/VegCore.ERD.mwb: regenerated exports and udpated image map

schemas/VegCore/VegCore.ERD.mwb: source: made name optional because some sources (e.g. records) don't have a name, and are instead identified differently. instead require name in applicable subclasses. source subclasses: added unique constraints on parent/name since the name is presumed to be identifying within the parent entity.

schemas/VegCore/VegCore.ERD.mwb: party: added separate person subclass, which has the organization pointer. organization instead has a recursive parent pointer, to avoid mutual recursion between party and organization.