making a RebuildCause and making that cause extend upstream cause. Gives us a little more UI love
Merge branch 'master' of https://github.com/JoelJ/rebuild-plugin

Conflicts:
	src/main/java/com/sonyericsson/rebuild/RebuildAction.java

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>