Code review comment for lp:~nmb/bzr/script-test-mv

This branch adds an mv command to the shell-like tests in bzrlib/tests/script.py, along with three tests modeled on those of the rm command. It only implements the simplest ``mv name1 name2`` syntax, not the more compltete ``mv file1 file2 ... dir`` command. Scratch your own itch! :)