so that make(1) will run in an almost clean environment and enhance the
description of the test infrastructure.
Add the ability to have multiple tests carried out per test script.
Give some tests more meaningful names.
Fix the usage message from the test scripts.
Make it possible to pass several commands to the test scripts like:
'sh test.t setup run compare clean'.
shell meta characters it is not passed to the shell, but the command
is executed directly (given that the line is not a shell builtin) and
that the line with a meta character is passed to the shell.
