Fix camera receptor bug

[2424barrier]

Modifies the position at which the receptor sends signals for the digiline camera as the change in a49e4dd broke many existing builds that relied on it.

[SwissalpS]

I had a hard time accepting the old way, it felt wrong. Of course changing this does break existing builds.

[OgelGames]

I agree with @SwissalpS, the offset was confusing, hence the change. Also, that change was made over 3 years ago, so changing it back will break new builds, likely more than fixing old ones.

[cheapie]

The original reason for the offset was to allow for use of the camera as vehicle detection for traffic signals, like this:

However, upon thinking about this more, adding a single (0,-1,0) rule, in addition to the current ones, would also work just fine for this use. Does that sound acceptable? I can go come up with a PR (or have 2424barrier do one) if so.

[OgelGames]

adding a single (0,-1,0) rule, in addition to the current ones

Sounds like a good solution 👍