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.
Site updated at 2014-10-15 05:16:32 UTC
Merge pull request #1331 from Darkhogg/patch-1

Fixed setup_github_pages failing and not properly writing url to _config.yml
Site updated at 2014-11-11 16:20:16 UTC
Site updated at 2014-11-11 16:21:45 UTC
Site updated at 2014-11-11 16:22:28 UTC
Merge branch 'master' of github.com:ashish1099/ashish1099.github.io into source
Merge remote-tracking branch 'upstream/master' into source
Merge remote-tracking branch 'origin/source' into source
Edited the new post