Example implementation of stage0

Visual stimuli only, autoreward for all visual targets, 150 trials.

Trial logic
- [x] Single block, randomise target vs. non-target. Autoreward target
- [x] Variable pre-stimulus time, 0.5-6s from exponential distribution
- [x] Fixed pre-stimulus quiescent period (1.5s)
- [x] Fixed stimulus & response window time (1s)
- [x] Fixed post-response window time (3s)
- [x] Instruction trials not required for this block
- [x] Response window should be between 0.1-1s after stimulus onset

Visual stimulus
- [x] Duration 0.5s
- [x] Should be 50 degree circle
- [x] Target (moving right) vs. nontarget (moving down)
- [x] Should not be warped
- [x] Spatial frequency = 0.04 cycles/deg.
- [x] Temporal frequency = 2Hz
- [x] Flipped phase in half of trials.