Merged requested to merge ATLAS-EGamma/athena:GSF_index_no_need_alligned into master
The arrays we were using to do the mapping from the triangular array index of the distance matrix
to the (i,j) of the component pair are not used in a way that we need to make them
For the float ones is another story and there is an ongoing discussion on possible missed optimisations.
Also added a few comments on what the code is doing.