Integrated bytecode-compatibility-transformer that allows core to
do signature changes on properties that plugins might depend on.

The library performs necessary bytecode transformation to achieve this.

The first use of this is to fix plugins that looks for List
AbstractProject.triggers, thereby resolving JENKINS-18677.

For the time being, I'm not loading such compatibility annotations from
plugins, but I did code that in PluginManager. Let's see how this
feature work out for a while in the core, and if it looks stable and
solid, we'll open it up to plugins at that point.

Improve search to look for items inside ItemGroup

Added a new overloaded version that works on a project.

Updated CoreEnvironmentContributor accordingly.

Avoid deprecated junit.framework.Assert, use org.junit.Assert instead

Add tests for Project class

Add tests for Node class

This reverts commit 1a6f3dfa.
forgot to add this file

Conflicts:
	changelog.html

The code is smart enough to compute a minimum set of builds to remove to
restore order consistency.

Fix javadoc warnings in hudson.model.Queue