Merge wiki documentation from -core and -core.wiki repo

There seem to be some problems in keeping the live wiki and the stored stuff from wiki in the same state. I've extracted all changes which seemed to be relevant with their respective author. But it seems that I couldn't find all author information.

The merged result still has to be pushed to the live wiki:

    git clone git@github.com:mupen64plus/mupen64plus-core.git
    git clone git@github.com:mupen64plus/mupen64plus-core.wiki.git
    rm -rf mupen64plus-core.wiki/*
    cp -r mupen64plus-core/doc/emuwiki-api-doc/* mupen64plus-core.wiki/
    git --work-tree=mupen64plus-core.wiki --git-dir=mupen64plus-core.wiki/.git add .
    git --work-tree=mupen64plus-core.wiki --git-dir=mupen64plus-core.wiki/.git commit -a -m "Push mupen64plus-core changes to wiki"
    git --work-tree=mupen64plus-core.wiki --git-dir=mupen64plus-core.wiki/.git push origin master