Update the ABT test for "Sokoloff - short formula model".
For PET processing, added new logic - if user specifies the concentration conversion other than "Signal Values" - information dialog box pops up informing the user.  Then Signal is used for Concentration of Input function

Verified basic operation of the "T1-mapping using inversion recovery" model on the small phantom data.  "Modulus (1)" sub-method was used.

Upgraded the "AATH" to the new optimization approach:  Model calculation are performed by User-specified method.  Residual function estimates in terms of the original signal.

Restored the ABT subtest for this model.

Upgraded the "Modified Tofts model" {Ktrans,Ve,Va} to the new optimization approach:  Model calculation are performed by User-specified method.  Residual function estimates in terms of the original signal.
Restored the ABT subtest for this model.