- generalizes/cleans keventd support to also handle
        * rx stalls (and usb 2.0 transaction translator unplug)
        * rx memory shortfalls (latent bug Oliver noticed)
        * cleanup on device disconnect (quiesce first)
    - merges Brad's patch to use the IEEE802 "locally assigned" bit
    - fixes a couple minor bugs on error paths (leak, bogus diagnostic)
    - updates some comments