refactor(style): this restyles parts of the site's layout

fix(demo): removes md-active attribute from demo tabs and re-styles tabs

refactor(style): revises the site HTML for the toolbars

enhance(style): added angular logo and switched to red theme

enhance(style): updated toolbar colors for red theme

enhance(styles): revised styles for top toolbar buttons

enhance(ripple): adds a minimal timeout to make sure that updates are complete before creating ripple

feat(theming): adds md-theme-levels directive