#17 Added utility methods to CommonMockMultiRowResultSet

[Steven Blundy]

Needing the use of isBeforeFirst, isFirst, isLast, and
isAfterLast for a test, I added them to
CommonMockMultiRowResultSet myself. I had to change
the behavior of the myRowOffset pointer a little so that
it point base the last row when next() passed it. I have
a test case if anyone would like to see it.

[Steven Blundy]

Patch for file, run from cvsroot