scripts/realtime: let DEBUG environment variable override rtapi.ini
scripts/realtime: enable environment options to rtapi_msgd and rtapi_app

$MSGD_OPTS gets passed to the rtapi_msgd command line
$RTAPI_APP_OPTS gets passed to the rtapi_app command line
rtapi: export simple_strtol for RTAPI/userland too

this made the hm2_test load fail
tests/hm2_idrom: make it work with uthreads and new logging

dmesg is gone as far as RTAPI logging goes.

Do one RTAPI session per test, log to file, and investigate
file per test.