Better explanation of what this is for and what its status is

[danshearer]

The adaptor has a particular purpose as very fungible bit of wrapper code for very specific use cases of the System Modeller. Sometimes API calls that appear to be generally useful migrate from the Adaptor to the system modeller, but often uses of the Adaptor are more one-off.

This isn't obvious in the README. Need to explain more clearly the uses of the adaptor.