Add glossary of terms used in webDiplomacy

files added:
glossary.php
locales/English/glossary.php

files updated:
lib/html.php
locales/English/help.php

Mostly I modeled the glossary on the FAQ with one exception. Rather than
use javascript to hide/show definitions, I instead used php by adding a
query string to the url. Where $_GET['term'] = term, print the
definition. This has the benefit of opening the definition when clicking
from one to another. Also each term now has a unique url, which will be
handy for reference.

This glossary is intended for the new player of webDiplomacy, so it is
not exhaustive. It is primarily terms used in webDiplomacy games and
forums.