Nuttx.py fixes: Python 2.7 support (required for gcc-arm-toolchain from Terry Guo), fixed int parsing, show mybt by name

EKF bugfix: Replace all off-by-one (<=22 and <23) instances by correct check. Replace all badly-written <=21 (correct, but unreadable) code by < n_states

FMUv1 + FMUv2: Reduce excessively large OS stack sizes. Actual use was 800 bytes hpwork, 400 bytes lpwork, 1700 bytes in running system. This leaves 1K headroom per task

Remove a noisy debugging statement.

Critical coverity fixes.

we need to pass the ioctl through to the bus interface

thanks to Jon Challinger for noticing this bug

Cleanup px_uploader output.