Use valid css class names when pygments language contains invalid chars, eg html+jango
Fix tables alignments in Cucumber features
Remove redundant whitespace in a Cucumber feature
Point migration docs link to the actual docs

... not to a confusingly-similar docs page.
Ref: https://twitter.com/Thedeadlybutter/status/439862381964181504
Our CI server runs bundle install already. Don't need to do it in script/cibuild.
Merge pull request #2108 from slavapavlutin/refactor-cucumber-features
Update history to reflect merge of #2108 [ci skip]
Extract core extensions into a Utils module

Fixes #2111
Add Utils.stringify_hash_keys
Rename those Utils functions.
Use jekyll-sass-converter 1.0.0.rc3
Merge pull request #2112 from jekyll/no-core-ext
Update history to reflect merge of #2112 [ci skip]
Use the rake helper for mkdir as this version makes two folders on Windows
Merge pull request #2118 from mscharley/windows-support
Update history to reflect merge of #2118 [ci skip]
Properly clean path for Windows machines which is *nix-compliant.
Properly strip drive name from clean path when sanitizing path.
Remove obsolete `normalize_options`.
Trim trailing spaces and convert tabs to spaces.