sql_io.py: put_table(): MissingCastException: When casting, handle InvalidValueException by filtering out invalid values with invalid2null() in a loop

sql_io.py: cast_temp_col(): Run sql.update() in recover mode in case expr produces errors. Don't cache sql.update() in case this function will be called again after error recovery.

sql.py: Generalized FunctionValueException to InvalidValueException so that it will match all invalid-value errors, not just those occurring in user-defined functions

sql_io.py: put_table(): Removed no longer used sql.FunctionValueException handling, because type casting functions now do their own invalid value handling

db_xml.py: put_table(): Subsetting in_table: Call put_table() recursively using put_table_() to ensure that limit and start are reset to their default values, in case the table gets partitioned (which needs up-to-date limit and start values)

sql_io.py: put_table(): mk_main_select(): Fixed bug where the table of each cond needed to be changed to insert_in_table because mk_main_select() uses the distinct table rather than the full input table

sql_gen.py: with_table(): Support columns that are wrapped in a FunctionCall object

sql_gen.py: index_cols: Store just the name of the index column, and add the table in index_col(), in case the table is ever copied and renamed

Moved error tracking from sql.py to sql_io.py

sql_io.py: put_table(): Use sql.distinct_table() to uniquify input table, instead of DISTINCT ON. This avoids letting PostgreSQL create a sort temp table to store the output of the DISTINCT ON, which is not automatically removed until the end of the connection, causing database bloat that can use up the available disk space.