Merged revision(s) 1621540 from lucene/dev/trunk:
Update some build tools

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1621541 13f79535-47bb-0310-9956-ffa450edef68
Merged revision(s) 1621543 from lucene/dev/trunk:
Update to Clover 4.0.0 (and update license)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1621545 13f79535-47bb-0310-9956-ffa450edef68