Support to change directory.

[Kray-G]

The Feature

We would like to use it like this.

Directory.change("dirname") {
    // do something under the directory of "dirname".
};

FYI, This can be also written below as JavaScript-like in Kinx.
The meaning is exactly same.

Directory.change("dirname", function() {
    // do something under the directory of "dirname".
});

Additional Comment

This is a very basic functionality.
So I will port it back also to v1.0.x.