Added support for rdiscount

**Added support for rdiscount markdown titles** (check line 15)

*This is a new file because it's not compatible with the other version.*

Could be needed to specify the place of the main content of the page in the headers depending of the theme to prevent to break the TOC.

For example you may need to replace
```js
var headers = $('h1, h2, h3, h4, h5, h6').filter(function() {
```
by
```js
var headers = $(' .content h1, .content h2, .content h3, .content h4, .content h5, .content h6 ').filter(function() {
```
Rather than have a new file just for this one line, could we have something like:

```javascript
if (!this.id) {
   $(this).attr( "id", $(this).prev().attr( "name" ).replace(/\./g, "-") );
}
```

Or would that cause other problems?
(I'd also prefer to write it as `this.id = $(this).prev().attr( "name" ).replace(/\./g, "-")` to keep it consistent with the next line, what do you think?)