SOLR-5010: clean up plus POST support on schema/copyfields

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1501047 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5010: tweak CHANGES.txt entry to refer to full copyFields creation capabilities

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1501054 13f79535-47bb-0310-9956-ffa450edef68