6553961: java.util.zip.{CRC32,Adler32}.update(int) doc errors
6646605: Missing method ZipFile.getComment()
6841232: ZipFile should implement Closeable
4985614: Failure on calls to ZipFile constructor
5032358: "java.util.zip.ZipException: The system cannot find the file specified"
6846616: java/util/zip/ZipFile/ReadAfterClose.java failed after fix for 6735255
Summary: some misc bug/rfe fixes for zipfile
Reviewed-by: alanb