Update index.html

Changed the links in the sample to local links, since the raw files served by github are not well received by the browsers (for the css)
Switch to bootstrap 3 and custom toc

- removed the v2.3.2 themes
- removed tocify (used some home-made code instead)
- wip (todo better theme support)
fix #2
issue #1, attempt 1
Apache handler for strapdown. Automatically adds html around mark/strapdown files with .sd extension