The simple toggle, bound to Del, engages reverse on the selected engine,
but if it is engaged on either, disengages it on both, so you don't get
stuck in reverse when selecting engine.
I also removed the check of weight-on-wheels from the disengage case, so
you don't get stuck if somehow the aircraft still becomes airborne after
selecting reverse on the ground.
The finer control, bound to F1 and F2, only controls the selected engines
now. Previous version disengaged reverse for both engines when either
reached zero throttle-rev, which does not seem to be founded in reality
and does not make much sense. You can always use Del to disengage reverse
on both engines.
Now that PgUp/PgDn respect selected engines respects selected engines,
make the TOGA, MCT/FLX and CL shortcuts do so as well.
Idle binding is an exception, because both thrust levers must be set to
idle for spoilers to deploy while one is enough to disengage the A/THR
and you don't want to repeat TAM3054 just because you forgot the
re-select both engines.
