target absolute position hard coded

[rakithab]

The offset between hall center and target center

In the class remollBeamTarget.cc line 156
fMotherTargetAbsolutePosition = fTargetMothers[fActiveTargetMother].first->GetTranslation().z() - 4500;
This is not an issue as long as the offset between hall center and target center is fixed.
I'm posting this in case if we ended up changing the offset, we need to update the location