SOLR-4590, SOLR-5295, SOLR-5296, SOLR-5263, SOLR-5297, SOLR-5301, SOLR-5255, SOLR-5305, SOLR-5314: Merging r1526616, r1528433, r1528441, r1528461, r1528488, r1529341, r1529434, r1529503, r1530268 from branch_4x