fixes #286 nng_pair0_open (and all others) need man page

fixes #279 consider restructuring man sections

This represents a rather significant rework, and major editing
effort, for the entire set of manual pages.

All of the pages now have a section number in their filename;
this assists in some other tooling, particularly ebook generation
as every link needs to be programmatically modified when combined
into an ebook.

Section 5 is introduced, and populated with pages for the main
types, and all options are now documented.

Numerous errors have been corrected, including rewriting certain
portions such as the header section of the surveyor protocol.

Much work has been done to facilitate index generation, although
certainly more work remains here.

Every internal link within these pages now resolves; there are no
more dead links.  (This is required to generate Kindle format books.)

1 files changed, 60 insertions, 0 deletions

diff --git a/docs/man/nng_aio_count.3.adoc b/docs/man/nng_aio_count.3.adoc
new file mode 100644
index 00000000..dc467abd
--- /dev/null
+++ b/docs/man/nng_aio_count.3.adoc
@@ -0,0 +1,60 @@
+= nng_aio_count(3)
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This document is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+== NAME
+
+nng_aio_count - return number of bytes transferred
+
+== SYNOPSIS
+
+[source, c]
+----
+#include <nng/nng.h>
+
+size_t nng_aio_count(nng_aio *aio);
+----
+
+== DESCRIPTION
+
+The `nng_aio_count()` returns the number of bytes transferred by the
+asynchronous operation associated with the handle _aio_. 
+
+Some asynchronous operations do not provide meaningful data for this
+function; for example operations that establish connections do not
+transfer user data (they may transfer protocol data though) -- in this case
+this function will generally return zero.
+
+This function is most useful when used with operations that make use of
+of a scatter/gather vector (set by <<nng_aio_set_iov.3#,`nng_aio_set_iov()`>>).
+
+NOTE: The return value from this function is undefined if the operation
+has not completed yet.
+Either call this from the handle's completion callback,
+or after waiting for the operation to complete with
+<<nng_aio_wait.3#,`nng_aio_wait()`>>.
+
+== RETURN VALUES
+
+The number of bytes transferred by the operation.
+
+== ERRORS
+
+None.
+
+== SEE ALSO
+
+<<nng_aio_alloc.3#,nng_aio_alloc(3)>>,
+<<nng_aio_result.3#,nng_aio_result(3)>>,
+<<nng_aio_set_iov.3#,nng_aio_set_iov(3)>>,
+<<nng_aio_wait.3#,nng_aio_wait(3)>>,
+<<nng_strerror.3#,nng_strerror(3)>>,
+<<nng_aio.5#,nng_aio(5)>>,
+<<nng.7#,nng(7)>>