fixed a coding style issue: we did not declare C variables at the beg…

…inning of the current code block in ngx_http_lua_del_thread, reported by runner-mei in github issue openresty#93.

updated docs to reflect recent changes.

optimize: now we recycle the special flush buf and chain link for ngx…

….flush() to prevent request-scoped memory leaks when emitting long data streams to the downstream.

bugfix: timestamp could overflow on 32-bit systems in the shared dict…

… API; now we use 64-bit integers.

updated docs to reflect recent changes.

bumped the version number in docs.

updated docs to reflect recent changes.

bugfix: when the parent request takes a request body, the subrequest …

…does not take any bodies, and the subrequest's method is neither "PUT" nor "POST", then the subrequest will no longer inherit the parent request's request body. thanks 欧远宁 for reporting this issue.

bugfix: data might be accidentally read into the lua space on idle so…

…ckets when the last operation is a read operation *and* a read event suddenly arrives for edge-triggered event models. the same might also apply to write operations too. bugfix: invalid reads might happen in the reading iterators returned by the receiveuntil() method which could lead to segfaults.

added tests for the various "lua socket blah blah timed out" error me…

…ssages; also tweaked other cosocket test cases for different test modes.