Add specialized variations of assert

[stevenfeuerstein]

I suggest adding things like

assert_not_null
assert_null

etc. I also suggest adding some additional options like "include call stack" .

In case this helps, here's an assert package I wrote: https://livesql.oracle.com/apex/livesql/file/content_CFLUGC2RAJKP3RAF5XYUMTXE8.html

[martindsouza]

@stevenfeuerstein for the null and not_null assertions do you know if we can declare an "any" object type so we wouldn't have to overload all the assertion functions?

Overall though I'm still on the fence with this one. Have tagged it as a Future enhancement. Will wait to see if others up/down vote this idea.