RamInode is now a general RamInode with no data. RamFileInode is now
a inode for regular files. This is much cleaner and more intuitive
since there is no reason for most non-regular inodes to hold data
Vector.
Serial monitors can now be used as a output. This requires editing
init code for the stdio opening. Serial input is not supported, so qemu
still needs graphical window for ps/2 keyboard.