Two fixes - see description

1) Param.tau is non-integer for small sampling rates e.g. for 5 Hz and with the default 0.08 sec, it is 0.4, however circshift function wants to have integer steps to move the signal. So anything lower than 1 is now set to 1 and anything higher than one (in case it is non-integer) is rounded.
2) Now there is a check if there is AUX or SS channels, if nothing gives an error message (nothing to regress out with tCCA).