[material] Move all components to namespace Components
the constant component is already in the Components
namespace. It makes sense similar to the namespace FluidSystems
, especially as there might be even nameclashes between classes in Components
and FluidSystems
, e.g. there might be in the future a fluid system Air
consisting of components N2, O2, CO2, Ar, conflicting with the (pseudo-)component Air
.
Fixes #375 (closed).
Edited by Timo Koch