update boto & s3_cache.py
Remove bootstrap keyword
Added the very useful .animation-fill-mode() mixin

I think that's the only animation property that was missing and it's quite useful.

https://developer.mozilla.org/en-US/docs/Web/CSS/animation-fill-mode
Merge pull request #12829 from ZDroid/no-bs-keyword

Remove bootstrap keyword from package.json
Update load-grunt-tasks.
Bump grunt-jscs-checker.
Run `grunt update-shrinkwrap`.
Add docs.css in the CSSComb task.
Fixed flickering and simplified calculations

- Removed offending line causing a flicker to the default top state
- Simplified calculation of the top offset when in the bottom state
Run csscomb before cssmin.
Merge pull request #12861 from twbs/docs-csscomb

Add docs.css in the CSSComb task.
Fix for issue #12854 where push and pull resets

The col-*-push-0 and col-*-pull-0 classes try to reset the positioning using 0% but this prevents the opposite direction positioning to freeze and not being set correctly.
To fix that, these must set the position to auto instead of 0% with means left:auto and right:auto instead of left:0% and right:0%.
Break csslint targets.
Fix csslint errors.
Move csslint overrides in Gruntfile.js.

This works around https://github.com/gruntjs/grunt-contrib-csslint/issues/26
Add sitemap.xml and robots.txt files.
Fixes #12851: it's not a tumah
Merge pull request #12866 from twbs/sitemap

Add sitemap.xml and robots.txt files.
Merge pull request #12855 from lipis/patch-1

Added the very useful .animation-fill-mode() mixin
100% less tumah