Default example library prereq is now libcork

None of our projects uses glib anymore, they all use libcork instead.
Let's use that as the example library in the template.
All placeholders are now called APPNAME

There were a couple of places we were using "changeme" or
"PLEASE_DEFINE_APPNAME".  Now we're more consistent.
Sphinx library documentation

Before, the library was only documented in comments in the `ipset.h`
header file.  This patch extracts this out into a proper Sphinx
documentation set, with links where appropriate into the libcork
documentation.
Sphinx documentation for command-line utilities

This patch adds Sphinx versions of the documentation for each of the ipset
command-line utilities.  The documentation is just lifted from the existing help
text, and reformatted to be Sphinx-friendly.
Merge branch 'feature/dox' into develop

* feature/dox:
  Sphinx documentation for command-line utilities
  Sphinx library documentation
No default value for CMAKE_OSX_ARCHITECTURES

We no longer set a default value for CMAKE_OSX_ARCHITECTURES.  (Before,
we tried to set a default that would compile a universal binary.)  Now,
it's up to use to set this however you want.
Merge remote-tracking branch 'templates/c-template' into develop

* templates/c-template:
  No default value for CMAKE_OSX_ARCHITECTURES
  All placeholders are now called APPNAME
  Default example library prereq is now libcork

Conflicts:
	.gitignore
	CMakeLists.txt
	INSTALL
	src/CMakeLists.txt
Fix compiler warning on Linux GCC 4.1.2