Slicer3:Loadable Modules:Phase1

From Slicer3:Loadable_Modules:

   * runtime module discovery
   * module template
   * like CommandLineModuleFactory 

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Starting at ~900 in Applications/GUI/Slicer3.cxx, static modules load occurs.

Using vtkSys tools to list shared libraries present. Use itk::DyanmicLoader to open libraries and call our specified entry points.

The actions taken for each module to be added could be queried from the found shared library using a LoadableModuleInfo class. Some of the information a library should provide:

• vtkSlicerLogic pointer (maybe this is one of the defined entry points for a loadable module)
• methods to call on the Logic pointer
• vtkSlicerModulesGUI pointer (ditto)
• methods to call on the GUI pointer
• module name

LoadableModuleFactory (ala Libs/ModuleDescriptionParser/ModuleFactory.cxx) handles this.