Organize and split IB module logic into a JS file for code reuse.

The autoUpgrade property is also gone because it is not an
operation that could be applied during a nib compilation workflow;
it is an operation that would be performed on a source document.

Change-Id: I5a6e6455a3fa6d9ab120c17169430db5f38175dd
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>