Allow us to fit only a subset of coefficients while keeping the full model intact (for situations where we want to "freeze" the value of some parameters while fitting others).
Ensure that the bounds vector is returned in the exact order as the phi vector (particularly for cases where we're fitting only a subset of coefficients).
Also includes new unit tests and a set_bounds function in nems.priors.
This solves several problems:
Also includes new unit tests and a
set_boundsfunction innems.priors.Closes #26