implemented extendable context menus using the corresponding extension point and service.

org.fortiss.tooling.kernel.ui/trunk/plugin.xml

...oling.kernel.ui/trunk/schema/contextMenuContribution.exsd

.../tooling/kernel/ui/extension/IContextMenuContributor.java

.../kernel/ui/extension/data/ContextMenuContextProvider.java

...org/fortiss/tooling/kernel/ui/internal/ActionService.java

...ortiss/tooling/kernel/ui/internal/ContextMenuService.java

.../fortiss/tooling/kernel/ui/internal/NavigatorService.java

...ernel/ui/internal/views/NavigatorTreeContentProvider.java

.../kernel/ui/internal/views/NavigatorTreeLabelProvider.java

...s/tooling/kernel/ui/internal/views/NavigatorViewPart.java

...org/fortiss/tooling/kernel/ui/internal/views/NewMenu.java

...org/fortiss/tooling/kernel/ui/internal/views/package.html

...ortiss/tooling/kernel/ui/service/IContextMenuService.java

...fortiss/tooling/kernel/ui/util/EObjectSelectionUtils.java

...s/tooling/kernel/service/base/ObjectAwareServiceBase.java