Refactored FiniteElementResults

KeyValuePair iteration is used, rather than a loop of the keys followed
by a lookup of the value.  This should reduce the number of lookups, and
thus increase the speed.
Added GenericCrossSection

Cross section to which the raw Area, Iyy, Izz etc. values can be set
directly rather than being calculated from other properties.
Removed unnecessary comment
Added GenericCrossSection class to the project