Cut 0.7.0 release

[asottile]

:)

[bardo]

Seconded :)

[felipecabargas]

+1 here

[dahlia]

I will release 0.7.0 on this weekend.

[asottile]

fwiw @Yelp is currently using master in production and it seems to be working well

[dahlia]

Sorry for late release. I finally released 0.7.0! See also changelog and PyPI.