write out wavelet arrays

[MatthewWhiting]

It might be useful, more as a debugging tool, to write out the individual arrays of wavelet scales during the reconstruction. This would make it possible to look at how appropriate the reconstruction threshold is for the data in question.

This way, you'd get a cube of the same size as the input for each wavelet scale, and (potentially) for each iteration. The first iteration is probably the best to examine, as the full signal is there (the subsequent iterations have the previous reconstructions removed).

This would be controlled by an input parameter, and should probably write a warning for large files.

It might be good here to also write out the actual reconstruction threshold (or, equivalently, the mean/stddev values) for each wavelet array - these could just be written to screen (in verbose mode).