pyb.delay and pyb.udelay now use systick if IRQs are enabled, otherwise
they use a busy loop. Thus they work correctly when IRQs are disabled.
The busy loop is computed from the current CPU frequency, so works no
matter the CPU frequency.
I also removed trailing spaces from modpyb.c which affected a couple
of lines technically not part of this patch.
Tested using: https://github.com/dhylands/upy-examples/blob/master/micros_test.py
which eventually fails due to wraparound issues (I could fix the test to compensate
but didn't bother)
Blanket wide to all .c and .h files. Some files originating from ST are
difficult to deal with (license wise) so it was left out of those.
Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.