endpoint resolution by module

suppose you have two modules:

*main.py*
```python
from klein import Klein

app = Klein()

@app.route('/')
def home(request):
    return 'hello from main home'
```

and in a second module, you defined another home for a different home:

*blog.py*
```python
from main import app

@app.route('/blog_home')
def home(request):
    return 'hello from blog home'
```

in this case if you point your browser -or something else- to `/` or `/blog_home` in both case it will return `hello from blog home`

this patch fix this issue, hope you'll like it!