Script the import mode to merge keyed transforms

This script is the script version of the Update animation (keyed transforms) Import option which lets you import FBX files so that existing un-keyed transforms are not overwritten, and are instead preserved in their current state.

// Necessary for prompt mode or in cases where plug-in isn't loaded and the commands below are required
	//
	loadPlugin "fbxmaya"

	// Change the import mode to exclusively merge keyed transforms only
	//
	FBXImportMode -v exmergekeyedxforms;

	// Perform the import operation
	//
	FBXImport -f $fileName -importFormat "fbx";