refs #952 low hanging fruit
refs #952, remove _numPartitions
refs #952, attempt at refactoring some cursor code
refs #916, rename OpLogHelpers to OplogHelpers
refs #919, kill sanity check in shouldLogUpdateOp
refs #917, remove logop parameter from update.cpp, we always logop
Any code that used to pass in false was doing so on the local database
anyway, which is not logged
refs #959, use a count cursor for touch