upgraded lua-resty-mysql to 0.13.
renamed the "nonbuffered-upstream-truncation" patch to "upstream-truncation" patch; also fixed issues with chunked upstream response bodies. thanks Andy Yuan for reporting this issue in #24.
updated the dtrace patch to make the stap function ngx_chain_dump() print out info about the "last_buf" and "last_in_chain" flags in bufs.