Wrote an alternative to the rel_ops-like `cmp`-based comparison operator
templates that may or may not actually work
Translated the "ops" methods in groups.py to C++.  Now to figure out how to
integrate them into the rest of the code (and get a C++11 compiler)...
Implemented a class template that can be inherited to automatically provide
comparison operators defined in terms of a `cmp` method, all for the sake of
saving a few lines of code