Make theme be compatible with latest Octopress

According to these commits:

- imathis/octopress@73e540409ceb8bc18048b6a96a4b815fc303ea28
- imathis/octopress@0f1660437beba58cd2974f07270b19305b9bbfd9
- imathis/octopress@2d40f51bd2d0368ad89e6862e84681763669d709