Added Etienne's error messages to the vm, which give the name of the
tree6e1868306e9ffc06ca1eec138b5b0b46a3330dbd
-rw-r--r-- 10099 library.scm
-rw-r--r-- 65437 picobit-vm.c
-rw-r--r-- 107994 picobit.scm
-rw-r--r-- 388 red-green.scm
-rw-r--r-- 31589 robot.scm