Found a bug and here's how to fix

Sorry, I don't know anything about github or python really, so I'm probably submitting this improperly.

Markdown-PP doesn't work when a file has the wrong kind of encoding. This can be fixed by changing

```
       try:
            f = open(filename, "r")

``` 
to

```
       try:
            f = open(filename, "r", encoding='utf-8')
```
in the file Include.py.