add buildin controllers in add_controllers function
so that multiple calls of sweep.go() won't lose these controllers
add MonocularGrating stimulus
add monocular test in disparity tuning experiment
add param indices -1, 16, 17 in PSTHTuning
index -1 for background activity
index 16 for left stimulus activity
index 17 for right stimulus activity
add annotations for non-/dominant monocular response and background
response in disparity tuning
various GUI tweaks and fixes