s, 0 (don't use finite size corrections) or 
                1 (use finite size corrections) - optional
                (available only for spikes). Defaults 0.
 Output:
       C (magnitude of coherency frequency x channels x channels)
       phi (phase of coherency frequency x channels x channels)
       S12 (cross-spectral matrix frequency x channels x channels)
       f (frequencies)
       zerosp (1 for channels where no spikes were found, zero otherwise)
       confC (confidence level for C at 1-p %) -