Fixes for the LM63 dispersion CPMG model.
The 'r2' model parameter is now an array as there is one R2 value per magnetic field strength. And the 'rex' parameter has been renamed to 'phi_ex' and is scaled quadratically with the field strength within the optimisation target function.
Authored by: bugman 2013-05-23
Parent: [r19711]
Child: [r19713]
