Add Xof3 proportions to documentation

Fix gh-1
Remove the stray before/after3of9 selectors

These selectors aren't meant to be there.

Fix gh-2
Add `!important` to declarations

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

Fix gh-3
Update CHANGELOG
Add `component.json` to Bower ignores
v0.2.0