Turn off antialiasing for test robustness.
Merge pull request #1291 from fstoner/testEnhancements

Turn off antialiasing for test robustness.
Destroy scenes in tests that were not destroyed
Destroy contexts that were not destroyed
Fix scene leak in CesiumWidget
Fixed leaked canvases
Fix incorrect URL to CesiumWidget.css.
Merge pull request #1302 from AnalyticalGraphicsInc/fixCSSPath

Fix incorrect URL to CesiumWidget.css.
Merge pull request #1300 from AnalyticalGraphicsInc/testscontext

Fix widget and test WebGL context leak
Merge remote-tracking branch 'origin/master' into preprocess