Move pair-interaction code into listed-forces module

Did C++ conversion, added Doxygen, renamed functions to reflect that
they are now local to a source file, and put them into an anonymous
namespace.

Made glatnr() local to the listed-forces module.

Converted IS_LISTED_LJ_C to static function and made it local
to bonded module.

Removed temporary cycle-warning suppression.

Change-Id: If3a3045021fe7a3f1d67d14f2294551fc41b5422