Fix many typos.
Merge pull request #304 from waywardmonkeys/typo-fixes

Fix many typos.
Remove incorrect parenthesis in code sample
Remove `inline` keyword to make code ANSI C compatible. Closes #297.

The function nn_cmsg_nexthdr_ was the only inline function. It is
moved to global.c.
Fix m4 quoting issue in configure.ac (fixes #308)
Add SYNOPSIS section for nn_env documentation (fixes #294)
Update nn_pubsub.txt
Merge pull request #312 from ifesdjeen/patch-1

Update nn_pubsub.txt
Add missing device.h file to dist

Add src/devices/device.h to Makefile.am to fix broken "make dist" build.
Merge pull request #314 from vinoski/fix-dist

Add missing device.h file to dist