dicts.py: Added join()

sql.py: Added mk_flatten_mapping()

sql.py: put_table(): Renamed the copy of in_tables that gets modified to in_tables_, so that the original list can eventually be reused in joining together the input tables into a temp table

sql.py: run_query(): FunctionValueException: Also match "date/time field value out of range" errors

sql.py: put_table(): conds: Use a set instead of a list for faster checking of the "cond not in conds" assertion

sql.py: mk_select(): conds: Support containers of any iterable type

sql.py: put_table(): Made conds a list so that there can be multiple conditions on the same column

sql.py: mk_select(): conds is list of (key, value) tuples instead of dict (dict still supported for compatibility), so that there can be multiple conditions on the same column

sql.py: mk_select(): conds is list of (key, value) tuples instead of dict (dict still supported for compatibility), so that there can be multiple conditions on the same column

util.py: NamedTuple inherits from objects.BasicObject so that it's comparable and hashable. This fixes a bug in dicts.make_hashable() where the NamedTuple created for a dict would appear to be hashable but would always compare as unequal.