r axis length (in pixels) of the ellipse
  phi     - rotation angle (in radians) of semimajor axis to x-axis

 INPUTS [version 2]
  mRows   - number of rows in mask
  nCols   - number of columns in mask
  mu      - 1x2 vector representing the center of the ellipse
  C       - 2x2 cov matrix
  rad     - [2] Number of std to create the ellipse to

 OUTPUTS
  mask    - created image mask

 EXAMPLE
  mask = maskEllipse(  200, 200, 40, 100,  20, 15, pi/4 );
  figure(1); im(mask); [mu,C] = imMlGauss( mask, 0, 2 )