[BUG] signal reasignment not posible (box out of range)

[Mariculous]

Whilst invetigating another bug, I just noticed this one.

What happened?
I was trying to reassign a single signal but that did not seem to work at all.

How to reproduce?
- Open the reproduction case (yes, it is the same as the one I created to reproduce another bug)
- Reassign any single signal to the unused signalbox.
- - You will get an error stating "Cannot build this signal this far beyond any signalbox."

[jamespetts]

Thank you for the report: I believe that I have now fixed this. I should be grateful if you could re-test with the next nightly build.

[Mariculous]

Fixed.

However, "reassigning" a single signal to the same signalbox it is already connected to will raise "cannot transfer signals: unknown error"

Due to this infering unexpected behavior, it could quickly lead to some kind of "I don't know why but there seems to be something wrong in assignment" bugreports.
It should better of either not raise an error at all or raise a "no signals transfered. Source signalbox was the same as target." or something like this.

[jamespetts]

I have now modified the code so that no error message is given when attempting to reassign a signal to the signalbox to which it is already assigned. I should be grateful if you could re-test with the next nightly build.

[Mariculous]

Fixed