What changed in EDuke32, build by build

Make the save filename counter automatically take the highest number present so as to not fill in gaps (which would make sorting inaccurate)

Sort saves Z-A by filename and internally preserve the names of ones deemed unfit to display

implement isAutoSave for headers

Add userbyteversion to savegame header and userdef

Overload ptrsize as a bitfield

Change header string to "E32SAVEGAME" (but still accept "EDuke32SAVE")