Fix typo that snuck in sometime recently.  DHB

Signed-off-by: David Brainard <brainard@psych.upenn.edu>
Merge branch 'master' of https://github.com/DavidBrainard/BrainardLabToolbox
Merge branch 'master' of https://github.com/DavidBrainard/BrainardLabToolbox
Merge branch 'master' of https://github.com/DavidBrainard/BrainardLabToolbox
Fixed this in PTB, getting rid of it here.

Signed-off-by: David Brainard <brainard@psych.upenn.edu>