Change HDF5Loader to have ordered names (required to work in Data
Browsing). Change LoaderFactory to have loader which loads errors as
well.

Make final change from H5Loader to HDF5Loader (Peters one).
Merge branch 'master' of ssh://dascgitolite@dasc-git.diamond.ac.uk/scisoft/scisoft-core.git
Fixed problem with taking differences and gradients of views and added
unit tests