SDK: can create primitives geometries (Box, Sphere) in SceneExplorer
SDK: add action to Quad, Line geometries  in SceneExplorer and a NewGeometrySettingsTopComponent to configure the creation.
Merge pull request #149 from davidB/sdk_scene_addprimitives

SDK: scene add primitives
Merge pull request #4 from jMonkeyEngine/master

downstream merge