Add -v flag to log version to the console.

I learned the proper way to create pull requests, haha. I figured I'd recreate a pull request with *just* the version thing in it, as that's non-obtrusive and something I'd really like to see. It would help people debug cuz they would know what version they are on, and it's convenient, and pretty much expected, etc, etc.

It grabs the version from package.json, so you don't have to remember to increment the version # anywhere else.

Usage:

```
> dploy -v
v1.1.4
```

or

```
> dploy --version
v1.1.4
```