project.py --help - typerror type argument unexpected

`python tools\project.py --help`

```
Traceback (most recent call last):
  File "tools\project.py", line 64, in <module>
    help="use the mbed library build, instead of the sources")
  File "C:\Python27\lib\argparse.py", line 1294, in add_argument
    action = action_class(**kwargs)
TypeError: __init__() got an unexpected keyword argument 'type'
```

cc @theotherjimmy @sarahmarshy 
