CLSQL integration of CLSQL-USQL

I've integrated Marcus Pearce's UncommonSQL port, CLSQL-USQL, into
CLSQL. In discussions with Marcus and extensive rearranging of the
CLSQL code, I've made this the default CLSQL interface. The original
CLSQL interface is exported and available in the new CLSQL-CLASSIC
system.

I've reworked the MOP-layer and the CommonSQL-API now works with
Allegro. I've not yet tested with OpenMCL.

For people who have used the original, but orphaned, UncommonSQL
library, please use the CLSQL mail lists to send feature requests, bug
reports, and comments. The next step I'm working on is adding reader
macro syntax support to CLSQL's do-query and map-query macros for
further CommonSQL API compatibility. I believe Marcus has further
CommonSQL compatibility as a good and he has written useful a TODO
file.

The new version of CLSQL, v2.3.0, is now available for download at
http://www.clsql.b9.com.

Kevin