Removed comment about HBDropSlot backwards compatability
Removed comment about HBDropSlot backwards compatability

Turns out this change is compatible because all dropslots have type
"dropslot" and uses the parent block to parse its value. As a result,
the name change of HBDropSlot to DeviceDropSlot does not matter.

BirdBrainTechnologies/HummingbirdDragAndDrop-,BirdBrainTechnologies/HummingbirdDragAndDrop-,BirdBrainTechnologies/HummingbirdDragAndDrop-