Adapting EstimateScatter into a data corrections computation script

[robbietuk]

Addresses #70

Repurpose the EstimateScatter script to compute all correction factors in a single script. From before, the scatter estimation script computed 80% of all the correction factors as most are needed for the estimation. Everything except randoms computation from delays. This PR will adapt EstimateScatter.sh to compute all data corrections.

Major changes from EstimateScatter.sh

• Two files are output (if cleanup=1): the Multiplicative Factors and the Additive Sinogram. Both of these files are named as per script arguments.
• This ComputePoissonDataCorrections.sh calls the EstimateRandomsFromDelayed.sh and so a delayed sinogram is required instead of the randoms sinogram. EstimateRandomsFromDelayed.sh has recieved light changes.
• Updated the documentation.

[robbietuk]

Testing shows promise, I am able to compute data corrections easily from my data. I am happy to merge once I recheck it tomorrow.

[robbietuk]

are you saying that the scatter problem has disappeared with this?

Unfortunely not, that issue remains with this script for the XCAT data. This script simply combines all the data corrections into one.