COMPRESS-263 add boilerplate docs for DEFLATE

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/compress/trunk@1609881 13f79535-47bb-0310-9956-ffa450edef68
give credit to java.util.zip for DEFLATE but by now the gzip layer is ours

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/compress/trunk@1609882 13f79535-47bb-0310-9956-ffa450edef68