msit: First full release of the msit paradigm

This PsychoPy implementation of the Multi-source Interference Task (MSIT) conforms to the implementation described in Bush and Shin, 2006. The MSIT was developed as an all-purpose task to provide robust single-participant level activation of cognitive control and attentional regions in the brain (Bush and Shin, 2006). Early work with the MSIT suggests robust activation of regions associated with top-down control – regions that are often active when the DMN is inactive. See the repository README for more information.