Generate coefficients for 1D Savitzky-Golay smoothing filters

function c = generate_savitzkyGolay_coef1D(order,interval)

INPUT:
order = order of the polynomial
interval = the window size; *MUST* smaller than size(vIN)

OUTPUT:
c(ss,nn)= a matrix
Rows corresponds to coefficients for the target point, g_t, at different location of the window (up >> down: g_t moves from left to right)