Update to Jekyll v.3.0.0.

[skip sauce]

.gitignore

@@ -33,6 +33,9 @@ Thumbs.db
 .komodotools
 *.komodoproject
 
+# Jekyll metadata
+docs/.jekyll-metadata
+
 # Folders to ignore
 bower_components
 node_modules

.travis.yml

@@ -22,7 +22,7 @@ after_script:
   - if [ "$TRAVIS_REPO_SLUG" != twbs-savage/bootstrap ] && [ "$TWBS_TEST" = validate-html ] && [ $TWBS_DO_VALIDATOR -ne 0 ]; then ./test-infra/s3_cache.py upload rubygems; fi
 env:
   global:
-    - JEKYLL_VERSION="2.5.3"
+    - JEKYLL_VERSION="3.0.0"
     - ROUGE_VERSION="1.8.0"
     - SAUCE_USERNAME="bootstrap"
     - secure: "pJkBwnuae9dKU5tEcCqccfS1QQw7/meEcfz63fM7ba7QJNjoA6BaXj08L5Z3Vb5vBmVPwBawxo5Hp0jC0r/Z/O0hGnAmz/Cz09L+cy7dSAZ9x4hvZePSja/UAusaB5ogMoO8l2b773MzgQeSmrLbExr9BWLeqEfjC2hFgdgHLaQ="

README.md

@@ -78,7 +78,7 @@ Bootstrap's documentation, included in this repo in the root directory, is built
 
 ### Running documentation locally
 
-1. If necessary, [install Jekyll](http://jekyllrb.com/docs/installation) (requires v2.5.x).
+1. If necessary, [install Jekyll](http://jekyllrb.com/docs/installation) (requires v3.0.x).
    **Note for Windows users:** Read [this unofficial guide](http://jekyll-windows.juthilo.com/) to get Jekyll up and running without problems.
 2. Install the Ruby-based syntax highlighter, [Rouge](https://github.com/jneen/rouge), with `gem install rouge`.
 3. From the root `/bootstrap` directory, run `jekyll serve` in the command line.