Small optimization to Matrix4.fromTranslationQuaternionRotationScale.
loadJson did not properly add the Accept header when no headers were provided.
Merge pull request #1280 from AnalyticalGraphicsInc/fixLoadJson

loadJson did not properly add the Accept header when no headers were provided.
Inline quaternion to rotation matrix in fromTranslationQuaternionRotationScale.
Merge pull request #1281 from AnalyticalGraphicsInc/matrixOpt

Translation-Quaternion Rotation-Scale
Merge branch 'master' into splines
Remove private variable from Spline.