SOLR-6554: Speed up overseer operations

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1646493 13f79535-47bb-0310-9956-ffa450edef68
Compare canonical paths instead of absolute paths

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1646494 13f79535-47bb-0310-9956-ffa450edef68
put a really simple html doc in exampledocs for using in ref guide examples (merge r1646116)


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1646496 13f79535-47bb-0310-9956-ffa450edef68