Patch for streaming resultsets

Hello folks,

I've made a patch against the current CVS version of the JDBC driver,
which, based upon Nick Ferrier's patch (thanks!), which adds
streaming result sets to the driver.
I've made some modifications to the build file, too, as in it's
current version it's not able to build clean for JDBC3. I think
I fixed that.
Another thing I added are three properties which can be included
inside the URL:

 defaultFetchSize=<int>

sets the fetch size default to <int>.

 forceFetchSize=<boolean>

in case this property is true, the driver ignores all setFetchSize()
API calls from the application. It can be used to get apps, which
"know" the postgres driver, work though... :-)

 useServerPrepare=<never|always>

This on alters the behaviour of server prepared statements. The
default behaviour is that PreparedStatement's DO get prepared
on server side, and normal Statement's do NOT.
Setting this property to "never" switches server side preparation
off completely, whereas setting it to always even makes
normal Statements prepared ones (which can be nice in case of
ever and ever repeated queries such as queue lookups).

Please note that some parts of the source are commented out
for now, as I did not find a way to accomplish the declaration
of a cursor for a prepared statement. As for now, this seems
to be a feature in upcoming 7.3.2/7.4. But as soon as one of
these arrive, we just twig out these comments and there we go...

The patch is, as mentioned above, against the most actual CVS
version. A single file, PGResultSet.java, belongs into the
org/postgresql directory; it needs to be added to the
repository.

Again, a big thank you for Nick Ferrier, as he made the first
version of this; I cleaned it up and tested it quite
thoroughly, our own app as all of the test cases seem to work
flawlessly with it. It seems that I've broken not too much... :-)

have fun,

Patric