tnrs_db: Made wait option default to off to facilitate running tnrs_db by itself, rather than as part of an import

tnrs_db: Added wait option to have tnrs_db exit as soon as no more names are available. This is useful for running tnrs_db when there is no concurrent import running, and therefore no need to wait for new data.

tnrs_db: Fixed the time of the "Waited" message so it that the total_pause (containing the next wait) would be incremented after the message was displayed. Split the "Waited" and "Waiting" messages into two separate messages.

README.TXT: Data import: Added steps to back up the TNRS cache, since it takes a long time to recreate. This also enables syncing it with a local machine when `make backups/download` is run.

README.TXT: Documentation: Added instructions to import and scrub just the test taxonomic names

input.Makefile: Staging tables installation: uninstall: For the TNRS datasource, prompt the user before deleting the schema, since the data in it is not easily reconstructible from a flat file

sql.py: map_expr(): When matching without quotes, support names containing spaces by not matching words when preceded or followed by quotes

sql.py: Expressions: bool_re: Also match parentheses surrounding the boolean value

README.TXT: Data import: import_all: Don't run with & because this prevents the created jobs from being owned by the calling shell. Instead, import the TNRS names as a separate backgrounded step and wait for it to finish before starting import_all. Removed TNRS import steps from import_all since these are now invoked separately.

README.TXT: Data import: Run import_all in the background, because it needs to import all the taxonomic names synchronously before it can start the datasource import in the background