make_analytical_db: Automatically call export_analytical_db when finished

schemas/vegbien.sql: make_family_higher_plant_group(): Added `taxonepithet IS NOT NULL` filter, to allow make_analytical_db to proceed even when the NCBI import fails (leaving some nodes with rank = 'family' but no associated taxonepithet). The most recent NCBI import failed due to the search_path/DuplicateException bug resulting from the import schema and public being in the search_path together.

schemas/Makefile: Fixed bug where need `SHELL := /bin/bash` for \$(confirmRmPublicSchema) to work correctly

lib/common.Makefile: $(confirm): Added comment that this requires `SHELL := /bin/bash` to work correctly

import_all: after_import(): Added `make backups/vegbien.$version.backup/test`

sql.py: DbConn._db(): search_path: Don't append the existing search_path, because it usually includes the public schema, which is now different from the schema being imported into. This fixes a bug where sql.function_exists() would find public-schema functions in both the public schema and the import's schema because both were in the search_path, causing a DuplicateException "more than one function named ...". Note that the elements of the existing search_path are no longer needed now that vegbien_dest's $schemas includes $public. Also note that if an instance of DbConn does not specify the schemas param, the existing search_path will be left as-is rather than overwritten with an empty list.

README.TXT: Data import: recording the import times in inputs/import.stats.xls: Added step to determine the import date using import_date

import_date: Added note that Mac and Linux differ in the order they sort the logs in

README.TXT: Data import: recording the import times in inputs/import.stats.xls: Updated pattern for new log filename format

README.TXT: Data import: recording the import times in inputs/import.stats.xls: Removed extra ./ before bin/import_times