[wanproxy/wanproxy] 6d9a1e: Don't limit buffer offsets to unsigned int.

[Juli Mallett]

  Branch: refs/heads/master
  Home:   https://github.com/wanproxy/wanproxy
  Commit: 6d9a1e765eb99e228d335a857c223c2892cbc156
      https://github.com/wanproxy/wanproxy/commit/6d9a1e765eb99e228d335a857c223c2892cbc156
  Author: Juli Mallett <juli at clockworksquid.com>
  Date:   2015-07-08 (Wed, 08 Jul 2015)

  Changed paths:
    M common/buffer.h
    M common/test/buffer-ops1/buffer-ops1.cc
    M http/http_protocol.cc
    M http/http_server_pipe.cc
    M programs/xcdump/xcdump.cc
    M xcodec/xcodec_decoder.cc
    M xcodec/xcodec_encoder.cc

  Log Message:
  -----------
  Don't limit buffer offsets to unsigned int.

In particular, modify Buffer::find to use a size_t.  Some consumers
of the WANProxy codebase now occasionally need to work with data in
a Buffer in excess of 4GB.