Fixed class-based views support

#570 broke compatibility with bound view methods.

Simplified flask-admin case:

```python
from flask import Flask, Blueprint

app = Flask(__name__)

class Dummy(object):
    def __init__(self, app, name):
        self.name = name

        bp = Blueprint(name, __name__)
        bp.add_url_rule('/', 'view', self.view)
        bp.add_url_rule('/<test>/', 'view', self.view)

        app.register_blueprint(bp)

    def view(self, test=None):
        return 'hi'

obj1 = Dummy(app, 'test')
app.run(port=8002)
```

In Flask 0.9 it works as expected, but in Flask 0.10 it does not.

Cased by `is` check:
```python
> obj.view is obj.view
False
```