Change gh-pages URL(github.com to github.io).
added JGit support GithubRepoPlugin
added GithubRepoPluginSpec
added pushing to remote repository test
Merge

Conflicts:
	build.sbt
removed plugin.scala
modified build.sbt
Merge remote-tracking branch 'origin/master'

Conflicts:
	build.sbt
	project/plugins.sbt
	src/main/scala/plugin.scala