opToeplitz   Toeplitz matrix.
 
    OP = opToeplitz(R) creates an N-by-N circular Toeplitz
    operator from the N-vector R. The entries of R prescribe the
    first row of the operator.
 
    OP = opToeplitz(C,R) creates an symmetric M-by-M Toeplitz
    operator where M = length(C) and M = length(R). The entries of C
    prescribe the first column of the operator, and likewise, R
    prescribes the first row.
 
    The above calls are nearly idential to Matlab's built-in TOEPLITZ
    function.
 
    Additionally, each call above accepts an optional logical flag that
    indicates if the column are scaled to have unit 2-norm length:
 
    OP = opToeplitz(R,NORMALIZED)
    OP = opToeplitz(C,R,NORMALIZED)
 
    Multiplication in either mode is implemented using the fast
    Fourier transform