snappyHexMesh now generates a face-zone for the AMI-s, and createBaffles
and mergeOrSplitPoints -split are used to create the patches. Before,
snappy generated AMI patches directly, which were then converted to
AMI-s with createPatch.
This way, the AMI-s match exactly at the start of the simulation. For
more complicated cases that may be derived from this tutorial, this
could be important.