Change lighting so it looks more "natural"

Shades looked like a line across the speheres because the light source
was attached to a static point in the scene, now the light is attached
to the camera so the perspective looks more natural.
Merge branch 'issue_5' into light_fixes
Merge branch 'issue_5' into light_fixes
Merge branch 'issue_5' into light_fixes
Merge branch 'master' of git://github.com/qiime/emperor into light_fixes
Change position of the light when scaling

Not changing the position of the light when scaling caused the elements
in the scene to have "funny-looking" shadow; this was caused because the
light object wasn't changing it's current position.
Merge pull request #37 from ElDeveloper/light_fixes

Light fixes -- Lighting of the scene looks more natural