Package edit-server up for distribution on PyPI.

Hey there @gfxmonk!  Thanks for writing this -- I've been depending upon it for a couple of years now, and I feel like I should probably give you back at least a little effort in return. :heart:

This PR adds two files that allow you to distribute your package on PyPI.  If you're familiar with how packages are distributed on PyPI, please forgive me if I am going into too much detail.

Once you've merged this PR (assuming you want to), you can register your package on PyPI by running:

```
python setup.py sdist register
```

Then, to upload a new package to PyPI -- which you might want to do once after each time you bump the version number -- you can simply run:

```
python setup.py sdist upload
```

I've added a few comments below to explain a couple of configurable parameters for changing things like what the package is named on PyPI and what the name of the commandline app will be to help you out below.

Cheers, and let me know if you have any questions!
This will automatically create a command-line app named `edit_server` that runs your module's `main()` method.  For quite a while now, you haven't had to package-up pre-built scripts like the checked-in file [edit_server](https://github.com/gfxmonk/edit-server/blob/master/edit-server), and if you do it this way, it'll create the command-line executable in the appropriate bin directory for the user or virtual environment so the user doesn't even need to be aware of where the package was installed -- they can just run it by typing `edit_server` from the shell.