Optimize polyline collection bounding spheres.
Merge master into polylineBoundingSphere.
Clone bounding sphere after creating a command instead of union with previous.
Merge branch 'master' into polylineBoundingSphere
Add test.
Merge branch 'master' into polylineBoundingSphere
Update CHANGES.md.
Merge pull request #997 from AnalyticalGraphicsInc/polylineBoundingSphere

Optimize Polyline Bounding Spheres