No traceback on unknown subcommand, just report the error
Report README with paging
 - Display the README with paging if output is to a terminal
 - Code to determine terminal window size in util.py
Move testhelp tests down into test directory and make everything work
 - Move testhelp tests from testhelp.py to test/test_testhelp.py
 - Clean up util.terminal_size() to keep pep8 happy