Showing some Python package magic...

The code in `__init__.py` is executed whenever the package (the directory it's in) gets imported, e.g. `import app.handlers` or `from app.handlers import MainPage`. This makes it great for initialization logic _and_ whatever is imported in this file will be available on the corresponding imported module, i.e. if we `from pages import *` in here then `import app.handlers` elsewhere, `app.handlers.MainPage` will be `app.handlers.page.MainPage`.