Make FOV apply to the larger window dimension as discussed in #1591.
Remove the setter for .fovy on advice from @bagnell.
Merge remote-tracking branch 'origin/master' into fov

Conflicts:
	Source/Scene/SceneTransitioner.js
	Specs/Scene/PerspectiveFrustumSpec.js
Fix fovy computation.
Fix tests.
Change default view calculation in camera and for the home button.
Refactor CesiumWidget to calculate canvas size earlier.

Previously, the canvas would be left at its default size until the first render.  Now, the size is calculated immediately after adding the canvas to the DOM.
Fix broken path
Additional methods for matrix types.
Update CHANGES.md
Fix more tests.
Merge pull request #1912 from AnalyticalGraphicsInc/fov

FOV based on longer window dimension
Tweak CHANGES.md
Update CHANGES.md
Merge pull request #1924 from fstoner/matrices

Added fromCrossProduct to Matrix3 and add/subtract to all matrix types.
Merge remote-tracking branch 'origin/master' into gltf-8