* Menu always updates for file load... by doing the refresh in the drawing function, eep. Oh well.

* M_StartMessages when file loading goes wrong! (Determined by CONS_Alerts of warning level CONS_WARNING and CONS_ERROR happening after W_LoadWadFile has been called.)
* Now actively tries to keep your place on the menu if files are deleted between calls to preparefilemenu().
* More enums! DIR_ (for if you want to try embed more metadata in the dirmenu strings) and REFRESHDIR_ (for refreshing the menu and handling warnings).
* Handle changing size menu between calls to opendir() better.
* Don't crash on draw/enter attempt if one of the dirmenu's is null.
* Moved the addons menu to OP_MainMenu instead of MainMenu for now so it can be tested in MP without needing to mess with several menus.
* Display the amount of space used for serverinfo_pak's fileneeded on the addons menu, both visually and with a percentage.