FIX: timeout and RT calculation in wait_for_button_press

[rmc-law]

1. Original timed_out = t1 - t0 < timeout always returns True immediately if timeout is > 0. Changing the sign of the inequality to > only returns True when time elapsed (i.e., t1 - t0) is greater than the desired period (i.e., timeout)
2. Function original returns t1, which is less informative than reaction time, which is t1 - t0.