Implemented object quoting strategy

Cuurently, only postgres implements a form of quoting whereby mixed case object names and object names that start with numeric characters are quoted.

I added a new property for either a changelog or a changeset.
A user can choose, to keep the existing functionality for backwards compatibility, quote only reserved words or quote all object names.

This allows for a conssitent approach to quoting object names across all databases. I added suuport for seperate setting of the referenced table name and column names in a constraint as well. This allows the individual objects to be quoted if necessary.

Added precondition for checking what quoting strategy is set.
This is used for testing.