feat(ui-sref-active): improve performance by reducing $watches fix(ui-sref-active): Avoid add/remove class race condition refactor(ui-sref-active): Apply all CSS changes in a single `$evalAsync`
feat(ui-sref-active): improve performance by reducing $watches
fix(ui-sref-active): Avoid add/remove class race condition
refactor(ui-sref-active): Apply all CSS changes in a single `$evalAsync`

See also: 6a9d9ae #1997 #2503 #1997 #2012

Closes #2777

mattlewis92/ui-router,angular-ui/ui-router,fpipita/ui-router,fpipita/ui-router,angular-ui/ui-router,codersongs/codersongs.github.io,angular-ui/ui-router,codersongs/codersongs.github.io,fpipita/ui-router,mattlewis92/ui-router