Revise interfaces. Breaking changes!

The most frequently used commands now take map[string]any as an argument vs being a method of Config.
Go's type checking is too strict to support Config as a general alias for map[string]any.

v0.9.2

Made Update recursive and added Get method (also recursive)
Updated README.

Fix go.mod module path

Hopefully fixes import failures.

v0.9.0

First release of this package