Profanity for a cleaner content, out of the box

Hello,

I've added a profanity filter for obscuring harsh words from posts written in the Ghost blog, to make the blog posts more cleaner.

The sole focus of Ghost is on the simplicity and the ease of composing - keeping this in mind, I've implemented a feature that makes the internet a more cleaner place to read - I've integrated the profanity-middleware NodeJS module as a default, which can be disabled in the settings.

On a technical note, the module works as a middleware, which makes it compatible with the existing Ghost architecture. Profanity is filtered upon 'save' of a post from admin (not while reading the content for display) - this is done to reduce the need for multiple parsing.

I have seen the Road Map and gone through the blogs for Ghost - and I'm aware that there will be a commenting system in Ghost at a later stage - This middleware will work seamlessly even then.

I believe this could add value to the Ghost platform. I'd love to get feedback, if any.

Cheers!

![dxq6km](https://cloud.githubusercontent.com/assets/7126758/3350932/4fc22752-f9e5-11e3-81e1-5b6f8461c2da.png)