perhaps '.' is on your PATH env?

otherwise the path to ./mal* & friends is not found, example,
```
    Le programme malg                                                         # features/cli.py:15
    Ayant démarré                                                             # features/cli.py:26
    Traceback (most recent call last):
      File "/Users/dingo1/.virtualenvs/microalg/lib/python2.7/site-packages/lettuce/core.py", line 144, in __call__
        ret = self.function(self.step, *args, **kw)
      File "/Users/dingo1/Code/Microalg/features/cli.py", line 28, in ayant_demarre
        timeout=world.timeout)
      File "/Users/dingo1/.virtualenvs/microalg/lib/python2.7/site-packages/pexpect/__init__.py", line 485, in __init__
        self._spawn(command, args)
      File "/Users/dingo1/.virtualenvs/microalg/lib/python2.7/site-packages/pexpect/__init__.py", line 590, in _spawn
        'executable: %s.' % self.command)
    ExceptionPexpect: The command was not found or was not executable: malg.
```