Change TogglerScannable to not have an empty OutputFormat
BLVII-162 (8.40) added TimeDelayScannable.

Added a scannable that is busy for the time provided in asyncMoveTo().
Initially designed to be used in a ScannableGroup to represent the fast
shutter on I07 that will be opened and closed at each scan point.
Changed order in TogglerScannable Hook enum

Changed to the order to better reflect the order they're called
(no real functional change, but it may be a little confusing otherwise)
Merge branch 'gda-8.40'