@michaelcahill, I noticed zoom was complaining that strcmp in get/set key was taking up a big chunk of time, and it turns out that clang isn't inlining the calls. Here's a rework of that, ready to merge if you agree.

There are some minor cleanups along the way:

• always set fmt at the start of the function, based on WT_CURSOR_RAW_OK
• always check S first, then u, then r