Add Xof3 proportions to documentation

Fix gh-3
Remove the stray size3of9 selectors

This selector isn't meant to be there.

Fix gh-4
Add `!important` to `sizeXofY` declarations

Make sure that the width is always applied and not overridden by styles
in a component that may be bound to the same element.

Fix gh-5
Update CHANGELOG
Add `component.json` to Bower ignores
v0.4.0