Adding check to ensure octopress fork is not out of date.

Fixes #37.
Adding Amazon affiliate links.
Adding valid alt link to AMZN affiliate img tags.
Changing site title and subtitle.
Renaming PNG to SVG before making changes.
Uses SVG instead of PNG for LaTeX images.

Also

- Removes all use of KaTeX, though this will be restored.
- Removes KaTeX css/js and fonts.
- Removes unused PNG files in content/latex_images.
- Manually sets width of SVG in <img> tags to a scaled up size.
- Sets max-width to 100% to eliminate overflow.
- Updates scripts to create and reference SVG files.

Fixes #38.