Force time stamp of a given stream to align with the events of another stream

[arnodelorme]

Sometimes one might want to use time stamps of the event markers of a different stream as ground truth. For example in an audio maze task (more info at https://sccn.ucsd.edu/wiki/Audiomaze)

• A wall detector detected detected wall touch at 6 ms.
• A screen refresh happened to show visual feedback to the subject at 16 ms.
• In this case, behaviorally-defined 'wall touch feedback' should be registered as 16 ms (which is his claim), not 6 ms.

This could be left as an option in the importer