SOLR-5631: Add support for FreeTextSuggester

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1558635 13f79535-47bb-0310-9956-ffa450edef68
SOLR-1301: Move CHANGES entry to 4.7

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1558647 13f79535-47bb-0310-9956-ffa450edef68
SOLR-1301: Throw an error if HdfsDirectoryFactory is not configured for now.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1558670 13f79535-47bb-0310-9956-ffa450edef68