convTime2ValidEpochs

  convTime2ValidEpochs returns valid epoch numbers within a time range

  Example:
  epochs=convTime2ValidEpochs(chan, start, stop)
  where
    chan is a sigTOOL channel object
    start & stop are the beginning and end times for the search.

  Returns valid epoch numbers where
                start <= chan.tim(:, 1) < stop 

  Toolboxes required: None
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  Author: Malcolm Lidierth 12/07
  Copyright © The Author & King’s College London 2007
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  Acknowledgements:
  Revisions: