0032954: Tool for applying transformation to OCAF document

0032954: Tool for applying transformation to OCAF document

New XCAFDoc classes:
- XCAFDoc_AssemblyIterator: iterator in depth along the assembly tree
- XCAFDoc_AssemblyGraph: assembly graph with iterator
- XCAFDoc_AssemblyTool: provides generic methods for traversing assembly tree and graph

A method for re-scaling (sub-)assembly geometry is added to XCAFDoc_Editor.

New DRAW commands:
- XDumpAssemblyTree: iterates through the assembly tree in depth up to the specified level, if any
- XDumpAssemblyGraph: prints assembly graph structure
- XDumpNomenclature: prints number of (sub-)assembly/part instances
- XRescaleGeometry: applies geometrical scale to (sub-)assembly