refactor(ripple): adds support for non-fixed tabs

Closes #825.
Closes #460.
According to the spec, the ink bar can be the color of the selected tab color (in this case, white), or the secondary color (in this case, yellow).

http://www.google.com/design/spec/components/tabs.html#tabs-specs

These colors were changed temporarily to make this demo look a bit more cohesive; however, they will likely be changing again in the fix for #811.