Add timeout when receiver is not found after 5 seconds

[moan0s]

This tries to solve the problem that a user not familiar with the setup forgot to activate the localite-flow but has a hard time of finding the source of the problem

[agricolab]

The receiver looks for the localite_marker stream using resolve_stream from pylsl. This function has an inbuilt waiting time, that is, how long it looks before returning an empty list. It always returns after the waittime.

That means: If the timeout is different than the wait-time, that'll cause issues. You might want to forward the timeout argument via the Receiver to resolve_streams, and catch the empty list in the Receiver (e.g. here instead of the Coil. Alternatively, skip timeout completely, and just catch the empty list after the default wait time. That'll do the job of informing the examiner with an more informative error message.

https://github.com/labstreaminglayer/liblsl-Python/blob/master/pylsl/pylsl.py#L535-L538