Splitting fixes - avoid optim fail in effective splitting example

These changes:

* Make the effective splitting example give smooth results for the FD Gaussian wavelet version by making the simplex optimiser stricter by default.
* Allows MS_measure_trace_splitting to output something like an error surface.
* Allows the simplex options to be set by the user.
* Fixes vararg handling in a couple of cases
* Adds graphical output examples in the effective splitting example (these should be moved and integrated into the documentation).

It should be merged into the ongoing splitting changes.