Fixed blog_url not returning & rake setup_github_pages failing

When executing `rake setup_github_pages`, an error tells that `url` don't exist. The reference to that variable has been changed to a call to `blog_url`.

The function `blog_url` was not returning anything, failing to properly write the `_config.yml` file. It now does return what should have.
Fixed blog_url when user contains uppercase letters
Made blog_url becalled just once...

...and stored in the `url` variable.
Reversed update_style copy direction to correctly restore the sass.old/custom files to the new sass/custom folder
Fix typo in update_style copy command
Merge pull request #1489 from duckpuppy/fix-update_style

Reversed update_style copy direction to correctly restore the sass.old/custom files to the new sass/custom folder
Use correct time in log message for Github deploy
Merge pull request #1563 from tsmacdonald/master

Use correct time in log message for Github deploy
Update gist tag url to githubusercontent.com
fix script_url_for url bug
Merge pull request #1567 from howiehu/fix-gist-url-bug

Update gist tag url to githubusercontent.com
Refactoring addSidebarToggler()
Merge pull request #1586 from simonewebdesign/master

Refactoring addSidebarToggler()
Initial update to be compatible with Jekyll 2
Added jekyll-sitemap, jekyll-date-format, and updated gems
No longer including Gemfile.lock. Turns out that was a bad idea.
Merge pull request #1589 from imathis/jekyll-2

Jekyll 2.0 compatability
Replaced date plugin with jekyll-date-format
Removed date plugin, added excerpt separator default
Update `paginate_path` comment based on default value