Do not skip first mapping when making chain file
Created by: james-monkeyshines
I think this is a bug, but the logic is a bit complicated, so I'm not entirely sure. As I see it, the mappings are pulled into an array, then iterated over with an index, $i. The first mapping (ie $i == 0) is skipped, which seems like an error; the first mapping should be just as valid as the rest (?)