The new 16-bit residual code is a little bit slower, and it shows. I hope I can get this back up soon...

This gives one combined image that is convenient to load either with the test jig or with the Teensy Loader

This fixes some bug that I don't have time to investigate right now. Annoying! I suspect an assumption in usb_mem that I'm forgetting about.

Makes sure the firmware is running as fast as we expect

This seems cleaner, and now logging works before begin()

Our new

This allows the caller to do other things in-between programmed blocks, like showing status.