Short and long form parameters

[zeelot]

We should have a standard way of defining both the short and long form of a parameter. In my command, I should be able to do --force or -f and not have to handle both of those in my task, just define them. Maybe something as simple as this:

protected $_config = array('one', 'two');
protected $_short_forms = array(
    'one' => 'o', // Allows `-o foobar`
    'one' => array('o', 'oo'), // This allows multiple short forms of `--one`
);

This is related to #39 as I am splitting that one up.