parameter consistency check

[pkienzle]

parameters in the sasmodels description file must match the order of the parameters in the Iq and Iqxy calls.

Two alternatives:

(1) change the Iq/Iqxy? definition so that it takes a ParameterTable? struct, with parameters referenced in the code as p.name instead of name.

(2) parse the Iq/Iqxy? C code to make sure that the names of the parameters correspond exactly to the names of the parameters in the definition file.