Integrate as submodule of altair?

[joelostblom]

It would be cool if this package's functionality could be made available via a submodule in altair:

from altair import aly

aly.nan()

or maybe:

import altair as alt

alt.aly.nan()

It would put much higher demands on the code quality and stability so less rapid development, but could still be labeled as a more experimental part of the altair package if everything was contained in a submodule/folder. It would increase the visibility of these functions a lot which I think would be useful for many people