Fix T27909- Perfusion DataFit View: Incorrect calculation for the maximum signal for the Two Step Linear Model.
Summary: Recalculate the maximum signal. Rewrite formulas accordingly. Rename parameters in consistentence with ComputeModelfunction.
Test Plan: Manual
Reviewers: floca
Reviewed By: floca
Differential Revision: https://phabricator.mitk.org/D436