Use tolerances even when changing simulation algorithm.

[luciansmith]

If a SED-ML file describes the use of (say) LSODA with certain tolerances, it will not use those tolerances when using a simulator that uses CVODE.

This is great when the described tolerances are less strict than the defaults for the simulator, but not great when the tolerances are more strict. The algorithm should check if the new tolerances are stricter, and, if so, apply them.