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Addresses https://github.com/ChrisKnott/Eel/issues/572. Regression of https://github.com/ChrisKnott/Eel/issues/211 caused by https://github.com/ChrisKnott/Eel/pull/229. [Currently, eel routes are added via `bottle.route()`](https://github.com/ChrisKnott/Eel/blob/414b2c3858ff95e3811089d4bd797910b6934f1a/eel/__init__.py#L174), which only adds routes to the default app. This means passing any non default instance...

**Eel version** `0.14.0` **Describe the bug** `eel.start()` uses `bottle.route()` to add eel routes, which only adds routes to the default `Bottle` application. Thus, if a non default instance of `bottle.Bottle`...