Adding Eiffel & updating Modula-3#68

After seeing that there was a C++ version with a memory pool, I decided to try a Modula-3 version with a memory pool. It improves its performance significantly. I'm adding a first Eiffel version, but I will probably revise it over time. There are some differences that say it can't merge automatically. I thought I fixed them using `git mergetool` but it still says they're there. When I look at what shows up below, I'm a bit baffled that I'm seeing commits from May or October. The only thing I want to add is the material from November. I thought we were already up-to-date on that, so I'm a little confused. Do you know what's going on?