sql_gen.py: ColDict.__setitem__(): Fixed bug where None value should not be replaced with column default value if column has no underlying table

sql.py: DbConn.col_info(): If column does not exist, raise sql_gen.NoUnderlyingTableException

sql_io.py: put_table(): In log messages, use `.to_str(db)` instead of repr() where possible to use the SQL syntax of the DB driver

sql_io.py: put_table(): ignore(): Replacing invalid value with NULL in nullable column: Corrected log message to "Replacing invalid value ... with NULL in column ..." because the rows with that value are not ignored in that case

sql.py: run_query(): InvalidValueException: Parse any exception ending in "out of range", not just "field value out of range", in order to support errors that the timezone is out of range

schemas/py_functions.sql: _dateRange*(): Made functions STRICT because they return NULL on NULL input

sql_io.py: put(): Use a simple case of put_table(), which now supports everything put() needs. This will enable all row-based and column-based processing to be maintained in the same function, put_table(), and avoids the need to reimplement any column-based functionality (like SQL functions) in put().

xml_dom.py: NodeTextEntryIter: Allow empty values through as None, and instead filter them out in TextEntryOnlyIter using new helper function non_empty(). This allows XML functions to decide for themselves whether empty values should be filtered out, because process() will now no longer automatically remove them. This will enable process() to work with SQL functions, which must not have empty values filtered out because this will remove required, but nullable, arguments.

xml_func.py: Use conv_items() in every XML function that needs empty (NULL) entries removed, so that they are not dependent on what process() does to the items

sql_io.py: put_table(): ignore(): Support invalid literals in addition to invalid column values. This also allows put_table() to fully support being called by put().