Support for Oracle (9/10/11)

Hello Tomasz,

I just verified that the unit test still pass with the jtds version 1.2.7.

In addition to that I also added support for oracle 9/10/11 - all unit tests pass. 
I tested this with oracle 11, but this analytic function (row_num) is part of the SQL99 
standard which is available since Oracle 9 IIRC.

I also introduced a small helper class *) which generates the sql99 conform sql select statement  
with pagination support. This works for sql server 2008 as well as for oracle.

*) I thought introducing an additional SqlGenerator base class (AbstractSql99SqlGenerator) would be to much atm... ;-)

Hope this helps :)

Best regards,
Tom