Add mixin for :focus and :active IE7 compatibilty

- Combinations of &:hover, &:focus, and/or &:active -> @include
pseudo-focus
- &:focus and &:active ->@include pseudo-focus(false)
Additional cleanup of focos/active pseudo events

Rebraced some of tabbed interface that was affected.
Merge pull request #1294 from nschonni/add-focus-mixin-1293

Add focus mixin