Saving Active Dynamic model settings to FVX file:  corrected a design flaw.  Sometimes we change the number of Free and Output parameters in the models.  If this model was save previously to FVX file as an Active model the current version of FireVoxel often would not be able to load such FireVoxel file and it will be lost.  In the corrected version, only the warning that the Model design was changed would show but file would always be loaded.

Enabled loading of the GE-scanner diffusion dataset by providing a specialized procedure to load                 b-values from the private GE tags.

Sokoloff model (Long formula):  added additional user controls so the values of all parameters {K1,k2,k3} could be fixed during the optimization.  User simply set  k2_min = k2_max = Desired Value.

Sokoloff model (Short formula):  added additional user controls so the values of all parameters {K1,k2,k3} could be fixed during the optimization.  User simply set  k2_min = k2_max = Desired Value.