Extend support for Pointbase to support identity columns

On the subject of using Statement.getGenersatedKeys() (JDBC 3,0), here's some interesting links:

http://dev.mysql.com/tech-resources/articles/autoincrement-with-connectorj.html
http://java.sun.com/j2se/1.4.2/docs/api/java/sql/Statement.html#getGeneratedKeys()
http://java.sun.com/j2se/1.4.2/docs/api/java/sql/Statement.html#execute(java.lang.String,%20int)
http://java.sun.com/j2se/1.4.2/docs/api/java/sql/Statement.html#executeUpdate(java.lang.String,%20int)

In my humble opinion, it should be pretty straight-forward to have an initial implementation ready for use. Having said that, we should spend some time thinking about how to make this available (if at all), as clearly this would create a dependency on Java 1.4ff.

(Very) initial patch taht shows how to use the JDBC 3.0 API to have the generated identity values returned to the calling code. Please note that this code has not been tested yet (though it seems to be compiling on JDK 1.4.2 and later). In addition (as pointed out in the patch itself), I think we should either use reflection to avoid a compile time dependency on Java 1.4.x and later.

Updated patch with working solution. As a result, TC23 now completes successfully on Pointbase.

Whilst testing against mySQL, I cam to realize that some field types require 'special treatment'. As it stands right now, this patch now completes successfully against Pointbase and mySQL.

Final patch with changelog entries.

Updated patch, with small performance improvements in SQLEngine.