Updated get-database-type-specifier to handle text/longchar type
and refactored
* added a warning above defaulting to VARCHAR (since its probably NOT
what is expected on a bad type specifier).
* added a case where the specified type being a string, passes that
string directly (to better/more easily allow db-specific
data-types).
* added cases where longchar or text converts to text, and exported
those symbols (as this seemed type seemed to be missing from
fddl/oddl anyway).
* reorganized these default methods into a single method with a case
statement rather than many eql specified methods (about half the
code)
* updated the docs to use text instead of longchar since text is a
more standard db-type (pg,my,and ms all use text)