Remove bootstrap and jQuery

[n-gist]

Remove bootstrap

• [x] Copy used CSS to separate file
• [x] Remove CSS and JS from docs, write JS for navigation bar
• [ ] Update pages.sh
• [ ] Remove symlinks
• [ ] Rewrite navigation bar html and css completely (?)
• [ ] Remove/edit mentions about bootstrap in DEVELOP.md, LICENSE.txt, docs/LICENSE.txt, docs/site.css
• [ ] Make toggling navigation (using three lines button on narrow page width layout) animated again (?)

Remove jQuery

• [x] Remove from docs
• [x] Remove from gallery
• [ ] Remove from tests/hairlines.html, src/extras/hairlines.js, src/extras/super-annotations.js
• [ ] Update pages.sh
• [ ] Remove symlinks
• [ ] Remove/edit mentions about jQuery in DEVELOP.md, LICENSE.txt, docs/LICENSE.txt

[n-gist]

The most problematic part is hairlines plugin. I actually started rewriting js inside tests/hairlines.html, but after some time noticed that there is more in src/extras/hairlines.js and src/extras/super-annotations.js, so I decided to abandon it for now.

Other than that, bootstrap is removed, I checked all pages and it seems like everything looks identical to pre-changes