0030517: Inspectors - improvements in ShapeView plugin

0030517: Inspectors - improvements in ShapeView plugin

- implement "Explode" context menu action on a shape item in tree view. Calling this action cases build of the item subtree using TopExp::MapShapes by the type. (By default the tree generating uses TopoDS_Iterator)
- display properties of a selected tree item in Property Panel. (Similar to DFBrowser plugin).

(cherry picked from commit 2b4094183df26dfe0dae62f63822d7bf6d2214c6)
(cherry picked from commit a93268ba6cbde85f311fe698e186ea41da05efc2)