Reconstruction too memory-hungry

[MatthewWhiting]

Need to look closely at the memory usage of the reconstruction.

For instance, there is at least one needless allocation of the full size of the image - we don't need the residuals to be stored in an array. What would be better would be to have additional functions in getStats.cc that calculate the statistics of the differences between two arrays.

Note that the getMedianStats etc have an *additional* allocation of memory, so the way we are doing it now is to allocate an array, then allocate it again to find the stats. And that's all we do with that memory. Needless duplication.

We need to look in more detail at how the algorithm is implemented, as I'm sure there are other savings that can be achieved here.

[MatthewWhiting]

Some of this work has been done - look at what remains and see if the work for 1.1.14 is sufficient to close the ticket.

[MatthewWhiting]

The work for this ticket appears to be all done, so closing.