Changed site-title markup, mission style / text ..

I wrapped the site title in semantically meaningless <divs> instead of a
<header>, since we definitely want the <h1> to apply to the whole page,
but the body header is already taken by the side panel. I have the title
disappearing below desktop, and the ua-parser is adding a "hide-text"
class to the h1 so it remains but isn't visible.  I added a sentence to
the mission statement, dropped it into a blockquote, and de-sized it to
epsilon. I took away the "learn more" button because, well, it just
looks so damn nice on its own!