Disable unused local variable warning in Eclipse.

The latest version of Elipse claims ther are over 100 unread local variables in our code base, 0 of them appear to be accurate.  Since the warning is now useless, we should ignore it.
Add function to compute eigenvalues and eigenvectors for symmetric 3 by 3 matrices.
Add test to see if eigenvalues and eigenvectors are correctly computed.
Add more tests.
Add doc.
Update CHANGES.md.
Updates based on review.
Compeltely disable Eclipse JavaScript semantic validation in favor of JSHint.
Merge pull request #1224 from AnalyticalGraphicsInc/eigenDecomposition

Eigen decomposition
Merge pull request #1212 from AnalyticalGraphicsInc/shut-up-eclipse

Disable unused local variable warning in Eclipse.
Merge remote-tracking branch 'origin/master' into dynamicScene-fixes

Conflicts:
	CHANGES.md