take care of some MaxRanges feedback:

 * allow "none" to be expressed in config
 * send Accept-Ranges: none with MaxRanges none
 * stop accepting confusing/ambiguous "0", start accepting "unlimited".



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1166282 13f79535-47bb-0310-9956-ffa450edef68