Add Commit History View to build.

Lists Commit Status of the sha of the current build. Statueses are
grouped by commit context.

Conflicts:
	src/main/java/com/groupon/jenkins/dynamic/build/commithistory/CommitHistoryView.java
	src/main/resources/com/groupon/jenkins/dynamic/build/commithistory/CommitHistoryView/index.jelly
Merge pull request #82 from groupon/feature/commit_history_view

Add Commit History View to build.