simtb_padSM() - Pads SM dimensions to accomodate head translation Usage: >> SMnew = simtb_padSM(SM, Npad) INPUTS: SM = Spatial Maps, size [nC x nV*nV] Npad = Number of elements to add, should be EVEN. OUTPUTS: SMnew = padded spatial maps, size [nC x (nV+Npad)*(nV+Npad)] see also: simtb_addMotion(), simtb_makeMotParams()