returning -1 if no file can be allocated
fixing various bugs
fixed missing vmb_exit_hook
moving to version 1.8
adding directory to build mmixtools, first: mmoimg.exe
removing mmix (to mmix repository) moving src/mmix/bios/ to src/bios
ignoring files removing show_operating_system if undef VMB
fixing bugs in running, source options, breakpoints, debugging
changing MMIX_LOAD_FILE_LOC
fixing breakpoints in mmixvd
