add site policies adapted from TWDB site
mv url /policies -> /site-policies and replace old links in footer
rm old accessibility/privacy pages
site policy: Change minimum IE version from 8 -> 9
we don't support IE 8
simplify language about where the privacy and security policy applies
Merge branch 'master' of github.com:tnris/site-mockup
fix spacing in IE compatibility mode instructions part of browser policy
add an <h1> to home page (only visible to screen-readers)
clean up index.html indentation
add alt text for front page highlights images
accessibility: add link text for twitter/github links
accessibility: add alt text for news item thumbnail images
accessibility: screen readers should read About link as "about us"
cln: indentation
access: fix main content skip link location; change from <a> -> <span>
allow sortsite bot in robots.txt
Merge branch 'master' into catalogImages

Conflicts:
	content/markdown/news/2014-12-20-welcome-to-the-brand-new-tnris.md
closes #74 and closes #77, added images and alt tags, no more missing data catalog images, filled maps and data page