add scrollbar to code blocks

prevent code from running over the edge of the code block.
Merge pull request #8 from wywin/master

add scrollbar to code blocks
Check if DISQUS is defined before including disqus.html
Merge pull request #9 from xr09/master

Check if DISQUS is defined before including disqus.html
Moving changes to disqus.html
Merge pull request #10 from xr09/master

Moving changes to disqus.html
Merge pull request #12 from kenju254/master

Improved Documentation and Social
Big popular tags
Merge pull request #13 from xr09/master

Big popular tags
Title pull left, Show subtitle
Merge pull request #14 from xr09/master

Title pull left, Show subtitle
Merge remote-tracking branch 'upstream/master'