double_gauss_DoG_fit

  double_gauss_Dog_fit - Fits a double gaussian modulated by a difference of gaussians to data

   [OFFSET, DOUBLE_GAUSS_PARAMS, DOG_PARAMS, RFIT, RSQUARE] = DOUBLE_GAUSS_DOG_FIT(THETA, SF, R)

   (description of inputs/outputs here by Andrea)