ndo2db/queue: Cleanup old declarations, unused results.
ndo2db: A bit of cleanup to some old debug code.
ndo2db: Remove configure tests for nanosleep().

We no longer use nanosleep() so we don't need to detect it.

This reverts bd6ed8f5d2ba3a1bffed54c58c542022a63f431f and
8eaa5f365c3d40836a51d02bec55506bf82a42be.
ndo2db: Remove PostgreSQL support stub code.

ndo2db only supports MySQL.

A Postgres implementation had been started, but never finished. Since
our schema and many DB operations (e.g., auto increment,
last_insert_id) assume MySQL, and there hasn't been much recent demand
to support Postgres; remove the commented configure tests, DB server
type conditionals, and documentation references.

Removing the server type tests simplifies several chunks of the code,
which will make maintaining and tuning the DB code a bit easier.

Different storage backends _MAY_ _POSSIBLY_ be supported in the future.
The changes in this commit show some (but by no means all) operations
identified as DB specific, and may be helpful if implementing a new
backend.
ndo2db: More formatting cleanup.

There are enough edge cases and existing mixed formatting to make
astyle and other tools confused to the point that their output isn't
much of an improvement...