Fixed the bug in Wilhoit fitting.
Fixed the bug in Wilhoit fitting.

Subsequent elements of the A matrix are defined relative to previous elements,
so only the first needs to have the extra (cpInf-cp0) factor.

nickvandewiele/RMG-Py,comocheng/RMG-Py,chatelak/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,nickvandewiele/RMG-Py,nyee/RMG-Py,nyee/RMG-Py,comocheng/RMG-Py,pierrelb/RMG-Py,enochd/RMG-Py,faribas/RMG-Py,KEHANG/RMG-Py,KEHANG/RMG-Py,enochd/RMG-Py,faribas/RMG-Py