Changeset #699 fixes shared memory allocation: continous buffer with
requested size should be allocated or function failed.  For body longer
than 10 Mb, this allocation will definitely fails.

For body buffer it is not required to send it in a single continous buffer,
so, need to request minimum reasonable amount of shared memory and try to
extend it, if possible or allocate next buffer.

This closes #133 issue on GitHub.

It's not used since 3b77edf46701.

This closes #93 PR on GitHub.

It has the following structure and default values:

  {
      "http": {
          "header_read_timeout": 30,
          "body_read_timeout": 30,
          "send_timeout": 30,
          "idle_timeout": 180,
          "max_body_size": 8388608
      }
  }

The implementation of module was based on the assumption that PHP reads request
body and headers in the particular order.  For the POST request the body goes
before headers and vice versa for all other requests.

But as it appeared later, this order is unspecified and depends on many factors,
including the particular code of PHP application.  Among other factors those
can affect ordering:

 - presence of "Content-Type" header;
 - "variables_order" php.ini setting;
 - "enable_post_data_reading" php.ini setting;
 - reading php://input by application;

and this list can be incomplete.

As a temporary workaround, request body now is always put before headers and it
is gracefully skipped whenever PHP wants to get headers.

This closes #144 issue on GitHub.