Revision 162968

o changing MavenLifecycleContext to MavenGoalExecutionContext which is what
  it really is. Making way for the notion of a MavenSessionExecutionContext
  and it is looking like we will end up with two lifecycles. Where we are
  dealing with notions of goals and sessions: some operations need to be
  done at the session level and don't need to be repeated for the execution
  of every goal.