Motor can be tweaked/moved further when sitting on a limit switch

[tboegi]

A spin off from:
#211

General problem:
When a motor is sitting on a limit switch, the motorRecord inhibits/forbids/does not allow
movevements towards the same direction.
E.g. when LLS is activated, HOMR and JOGR do not command any motion
to the controller.
However, using TWR or putting a "lower value" into .VAL, .DVAL .RVAL field
will command the motor.
(Note that the exact combination is dependent on the sign of MRES and the .DIR field,
so that the problem is more complex)
One thing to keep in mind is that it should be possible to move away from the limit switch.
Another thing to remember is that some controllers only have one hardware signal,
and instead of filtering that in the controller specific driver, the motorRecord needs to fiddle with CDIR.

It would be good to have this fixed/improved.

[tboegi]

I just realized that the ess version already has this kind of check:
b47408f

https://github.com/EuropeanSpallationSource/motor/blob/ess-master/motorApp/MotorSrc/motorRecord.cc#L1046-L1480