Make a spec/compatibility page

[pbiggar]

Since each library is supposed to be pretty similar, they should have the same functions and mostly work the same.

Some ideas for how to help this:

A spec

Something like a yaml file with a list of functions, their arguments, and the doc strings for each one.

Shared test suite

If we had a single place (the spec yaml file?) with a set of expected input/output for each function, then we could possibly generate the tests for each language from them. This would keep them compatible and make it easier to add new libraries.

Compatibility page

List of functions and whether it's support in each variant. Could also include manual annotations when functions work differently in different versions.

Perhaps could be derived manually from the spec and test suite