revised patch for COPY

Here's another version of a patch that gives you COPY capabilities. The
difference is that in addition to the simple and default:

copyOut("tablename",outputStream);

you can also access other COPY features by supplying your own COPY query:

copyOutQuery("COPY "+tablename+" WITH OID TO STDOUT DELIMITERS '\t' WITH
NULL AS '\N'",outputStream);

This feature speeds up my application 40x and I bet it will be useful to
others as well. I wrote it to integrate cleanly into the driver, so
please let me know if its not appropriate for the main project.

Comments?

Mike Adler