This commit only fixes `Kernel` and ignores `DataHandling`. The
`Material` class has been changed to store the individual atoms
that make up the material and abstract the composite neutronic
information.

Still on the list of things to do is to return actual atoms which
will bring more of the error checking into a single location.

Refs #3515: Sample saving to NXS complete except SampleEnvironment. Refs #3669: Some code testing XML saving/parsing.

Refs #3515: Moved nexus CPP API over to a NexusCPP subfolder. Added to common include directories. Code in the Material object to save/load from Nexus

Rename Framework code directory to just that. Also delete Main and VS & Eclipse project file. Re #1881.

Adding the SampleEnvironment class plus changes around Geometry for the Monte Carlo work. Some changes in Geometry just clear warnings surrounding unitialized objects in copy constructors for class with virtual base classes. Other changes revolve around materials. Re #1212

Removed unused material fields from Object class, Re #1735

Added subfolders to src and inc in Geometry.vcproj
Tested with scons and VS sln builds

Enable reading of multiperiod data in LoadRaw. Different periods go into separate workspaces. Re #141. Also added initialize method to Workspace a la Algorithm to prevent workspaces being initialised more than once.