Merging several changes from trunk to the 2.4.x branch.

git-svn-id: https://svn.apache.org/repos/asf/ant/ivy/core/branches/2.4.x@1592626 13f79535-47bb-0310-9956-ffa450edef68
Merge upstream 2.4.x
FIX: regression introduced by IVY-1457, dependency management wasn't properly handled introducing lots of resolution failures

git-svn-id: https://svn.apache.org/repos/asf/ant/ivy/core/trunk@1592624 13f79535-47bb-0310-9956-ffa450edef68
Merge pull request #8 from sbt/wip/merge-upstream-2.4.x

Wip/merge upstream 2.4.x