* Add a mutable visitor
This adds the ability to mutate parsed sql queries.
Previously, only visitors taking an immutable reference to the visited structures were allowed.
* add utility functions for mutable visits
* bump version numbers
* Add derive based AST visitor
* Fix BigDecimal
* Fix no visitor feature
* Add test
* Rename visit_table to visit_relation
* Review feedback
* Add pre and post visit
Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>