Issue: IF Code to Parser Extensions

Since we are adding MediaWiki import support, we should finally release the parser extensions so that as much wiki-speak can be converted as possible. Since it is typically not used, the IF BB-Code should be moved to the parser extensions, and modified so that it uses pre-defined conditions. This way it can be permanently enabled without permissions concern.

The IF code could then easily be applied to templates to create MediaWiki's template conditional effect, which I have been dreading implementing separately. However, I will still have to add the legacy code so that it can be converted. {{if:X|Y|Z}} It uses a typical template format, so this should not be particularly difficult.