merge PetersonLian/jekyll-bootstrap@f04e8a83624e03b457388a17ed1e43e88bb62c61
fixing issue PetersonLian/jekyll-bootstrap#225 (deprecation...) by:
1,_config.yml; change "pygments: true" to "highlighter: pygments"
2,rss.xml&atom.xml; change "Layout: nil" to "Layout: null"