 is a cell array, returns Y which is the same 
    as X but excluding any empty cells.  
 
    An example of an input cell array X and the output Y is as follows:
 
        X{1} = [1 2 3 4 nan]';    X{2}=[]';    X{3}=[1 2];
        Y{1} = [1 2 3 4]';                     Y{2}=[1 2];
 
    Y=<a href="cellprune.html">CELLPRUNE</a>(X,M) will remove all cells with a length of less than M 
    points. In the above example, Y=<a href="cellprune.html">CELLPRUNE</a>(X,3) gives Y{1}=[1 2 3 4]'.
 
    [Y1,Y2,...YN]=<a