Added new experimental variables to exp file and PTB files.
Scell loop error removed.
Separated loading and building of textures into 2 files.
This has the added benefit of much faster transitions.
(See BF_display start in next commit)
Removed old code. (No functional changes)
Response variable name changed in process_response.
Removed breaks and changed if statement to switch in takekbinput.
Nonius/fixation is now presented until any key is pressed.
Stimulus response keys are left and right.
Demo mode is complete (tested and working on BF display)
Reduced delay between fixation and stimulus!!!!
(By separating loading and building textures into two steps)
Fixation is now shown until any key is pressed.
Stimulus is shown until left or right arrows are pressed.