element Geometry placement

[Laurie Nevay]

It's not possible to apply a transform to an 'element' element. Just now the geometry must be at the correct position / rotation for where it should be in the beam line.

Also the syntax is 'geometry' for the element but 'geometryFile' for the placement.

[Laurie Nevay]

The user should really prepare the geometry required - ie ensure their 'geometry' or objects are in a container at a suitable position / rotation. Aside from that, an alternative strategy using a placement globally in a gap is documented.

geometry is now geometryFile in the element class. Backwards compatibility retained.