Fix for the linear constraints for the 'R2eff' model.
The A and b matrices are no longer set to None, as this kills the auto-analysis or any analysis when constraints are turned on. Now the constraints 0 <= R2eff <= 200 and I0 >= 0 are used.
Authored by: bugman 2013-05-29
Parent: [r19777]
Child: [r19779]
