ss2Mss - Takes a ss object and translates it to an mss object

Input parameter
    - lsys:  lss-object, linear state-space model of type 'ss'
    - normtype - type of CPN norm. Currently only the 1-norm CPN is
        supported
Output parameter
     -msys: mss object - multilinear time-invariant state space model
Example: mysys=mss.ss2Mss(lsys,'1')