Improve use of P

[spmallette]

The use of P in could be better. You get ugly stuff like this right now:

(q/where :a (P/eq "b"))

That's just an example, but it shows how you have to use the String "b" rather than :b which would be more consistent with the rest of Ogre. There are similar weird bits with other aspects of P like:

(P/without [1])

where Ogre forces use of [] to denote the collection.