Added ext2 filesystem (read-only)

 Added ext2 filesystem (read-only).
This shall be sufficient for testing the object module loader?

1. Initialize a floppy in Linux with ext2 filesystem:
    % sudo mkfs -t ext2 /dev/fd0

2. Mount the floppy disk in Linux:
    % sudo mount /dev/fd0 /mnt

3. Copy compiled object module e.g. the 'hello.o' file to floppy disk:
    % sudo cp ~/hello.o /mnt
    % sudo umount /mnt

4. Mount disk in Real VMX using commands:
    -> fdDrvInit 0x26, 0x06
    -> pFdDev=fdDevCreate(0, 0, 0, 0)
    -> xbdBlkDevCreate(pFdDev, "/fd0")
    -> cd "/fd0"
    -> ld < hello.o

5. Display module info with:
    -> moudleShow(0, 1)

6. Call main function e.g. 'int main(void)':
    -> main