rainbow source hightlighting works better with 'lua' than generic.

using language="lua" instead of moonscript, as this works better than the generic
which was picking up earlier, and sice generic isn't being used, I've removed that
file.

Remove js/generic.js with Rainbow rules for generic
hide some '.extra-info' elements so they don't wrap to the next line
update bootstrap to v3.3.1
corrections after running index.html through HTML5 validator https://validator.nu
dowsize JSON image (to roughly the width of the content)
fix the navbar affix issue, when display is < 1200px

fixes #277
Merge pull request #314 from naartjie/website_tweaks

Some more gh-pages tweaks