- Half-convert FAT, Ext2 and NTFS filesytems to provide new ARC file infrastructure...

- Half-convert FAT, Ext2 and NTFS filesytems to provide new ARC file infrastructure. This allows removing some compatibility code in fs.c
- Remove use of FsOpenBootVolume() and FsOpenSystemVolume(). If callers don't want a file on boot volume, they need to use the new ArcOpen/ArcSeek/ArcRead/ArcClose functions instead of the old FsOpenFile/FsSetFilePointer/FsReadFile/FsCloseFile

svn path=/trunk/; revision=42537