Added a Materials file
Added a Materials file

-- contains material properties for ucn physics
-- contains a function to build all standard materials that can then just be picked in geometry macros rather than purposefully built. This means that the materials file is the place to change ucn material properties. So Geom file macro contains volume information (sizes etc...), materials file contains scattering lengths etc.., generateparticles macro contains the initial ucn distribution, and the simconfig file contains the overall simulation information (files to import, time to run for, etc...)

git-svn-id: 9e43e5c0b822a6a38dd81306e184699a3a573cb4@284 7850984a-0f19-49c7-84f0-416d0ede6f3e

mjrasobarnett/ucnsim,mjrasobarnett/ucnsim,mjrasobarnett/ucnsim