Changes to the site in prep for Section 508 release.
1. The "WCAG 2.0 bookmarklet" now referred to as the "Accessibility Auditor" bookmarklet on the home page.
2. WCAG 2.0 standard-level pages now combined into one, so Section 508 sits on the same level as it (and "Level AAA Summary", eg., becomes ambiguous).
3. Section 508 added as an option to the code sample textbox, "WCAG 2.0" prefixed to the other options.
4. Explanation of WCAG2 standard's position with relation to US Section 508 refresh, and EC Mandate M376 phase 2 (the European equivalent of 508).