Online docs are out of date

[kevinheavey]

The online docs are for version 0.9.0 while the latest release is 0.10.0.

For example, the API documentation contains no reference to the compose_left function.

[eriknw]

@mrocklin, suggestions?

[mrocklin]

I logged into RTD and switched us from Python 2 to Python 3 and things seem to be fine now (maybe?)

I also added @eriknw to maintainers (my apologies for not doing this half-a-decade-ago)

[eriknw]

Great, 0.10.0 appears to be up.

@kevinheavey's observation stands though: compose_left is missing. Fixed here: #494