Move range parse utilities to webmachine_util
Respond without chunked encoding for single range
Accept range end position which exceededs the resource size

RFC 2616 14.35.1 Byte Ranges

   If the last-byte-pos value is absent, or if the value is greater than
   or equal to the current length of the entity-body, last-byte-pos is
   taken to be equal to one less than the current length of the entity-
   body in bytes.
Add response switch to ignore a Range header