set pointer-event properties to make the site logo clickable.

- the user-nav div stretches over the main logo, making it non-clickable. disabling pointer events on user-nav makes the underlying logo clickable again. then, explicitly re-enable pointer-events for the descendants of user-nav div (i.e. the actual user nav buttons).
Merge pull request #1 from cnrk/feature/clickable-logo-65

set pointer-event properties to make the site logo clickable.