Default orientation for DataSource models

Eventually we plan on providing easy ways to specify orientation for Entity instances; but a small usability improvement in the short term is to just have the model stand up right if no orientation is provided.
Add back rotate when space is clicked. Add look when close to the ground and the sky is clicked.
Change look to use the geodesic normal to rotate about. Keep track of looking, panning, or rotating.
Re-add rotate in 3d tests (for mousing over space).
Stay in whatever mode the camera is in until the mouse is released.
Merge branch 'issue1940' into dataSource-model-defaults
Update default orientation after #1963
Merge remote-tracking branch 'origin/master' into dataSource-model-defaults
Improve camera for GeoJson example.
whitespace
Merge pull request #1972 from AnalyticalGraphicsInc/issue1971

Improve camera for GeoJson example.
Merge remote-tracking branch 'origin/master' into dataSource-model-defaults

Conflicts:
	CHANGES.md
Merge pull request #1938 from AnalyticalGraphicsInc/dataSource-model-defaults

Default orientation for DataSource models
Merge branch 'master' into camera-rotate-look
Make tilt mouse button also look when clicking the sky.
Add looking when clicking the sky to translate and tilt mouse buttons in Columbus View.
Use abs when checking against epsilon value for plane/terrain intersection.
Make the geodesic normal a constrained axis for interaction with the sky.
Fix bad doc links.
Merge pull request #1980 from AnalyticalGraphicsInc/issue1976

Fix bad doc links on Matrix classes.