inputs/VegBank/stemcount_/postprocess.sql: moved stemcount___parent index before the derived columns section because it does not depend on them

bugfix: inputs/VegBank/stemcount_/postprocess.sql: added missing index on taxonOccurrenceID, needed for the 1:many portion of the taxon_observation.** left-join

schemas/util.sql: added ||% operator to append to escaped strings (the % indicates an identifier, as in Perl hashes and one of the x86 assembler syntaxes for registers

bugfix: inputs/VegBank/taxon_observation.**/postprocess.sql: added sort_col (=identificationID) at beginning because column-based import will always sort a view by the first column, which may lead to slow query plans if the first column is not a joined table's pkey

inputs/VegBank/taxon_observation.**/postprocess.sql: documented that there is no row_num because left-join to stemcount_, stemlocation_ adds rows to each taxonobservation_

bugfix: inputs/VegBank/taxon_observation.**/postprocess.sql: removed row_num (=identificationID), because there is actually more than one row per VegBank taxonobservation_, so this does not properly enumerate the view rows. this is because there is a 1:many left-join to stemcount_, stemlocation_ which adds rows to each taxonobservation_. since the row_num is gone, any row-subsetting of the view using OFFSET will always need to materialize the entire view up to the OFFSET value. this works for smaller datasources like VegBank that fit almost entirely into one column-based import chunk (1 million rows), but not for larger datasources like FIA where it would be much slower to materialize all preceding 16 million rows on the last chunk (which is what OFFSET normally does with left-joins).

bugfix: inputs/VegBank/taxon_observation.**/: generated header.csv and related files, which were previously not generated because the error in `rm header.csv` aborted the runscript

bugfix: lib/runscripts/*: calls to rm: use `rm -f` instead to avoid an error (which aborts the program) if the file does not yet exist

inputs/VegBank/: added taxon_observation.** left-join of the tables, using the steps at http://wiki.vegpath.org/Left-joining_a_datasource

inputs/VegBank/taxonobservation_/create.sql: join starting with taxoninterpretation so that we can use the taxoninterpretation_id as the row_num (text strings, formed from concatenated #s cannot be used as a row_num). there is only 1 taxonobservation without a taxoninterpretation, so we can just include one row for each taxoninterpretation.