*Makefile: removed $(asAdmin), which is now set by lib/common.Makefile

lib/common.Makefile: added $(asAdmin)

bugfix: schemas/pg_hba.Mac.conf: changed postgres to _postgres for OS X 10.8 Mountain Lion

schemas/util.sql: added raise_undefined_column() for use in translating other exceptions to undefined_column

bin/map: map_table(): Resolve prefixes: combined db_xml.ColRef() constructor call with creation of args (as tuple) for clarity

bin/map: update_in_label(): use in_schema instead of the map spreadsheet column name when available, to allow using one spreadsheet for all datasources (which would not have a datasource-specific spreadsheet column name)

schemas/util.sql: added mk_source_col(), which uses the schema name instead of the map spreadsheet header to get the datasource name

schemas/util.sql: added table_schema()

added planning/goals/iPlant_BIEN_Proposal_Final.pdf with Mark's e-mail notes in iPlant_BIEN_Proposal_Final.pdf.notes.txt

bugfix: schemas/util.sql: mk_map_table(): add trigger to remove metadata value entries from the map spreadsheet as it's being imported, since these do not correspond to actual columns in the staging table and will produce an error when trying to rename nonexistent columns to them. note that these entries will still need to be included properly in VegBIEN.csv, which will require changes to the VegBIEN.csv make target.