Publish as a library

Would you mind if we publish the client as a library? So I can re-use the type defintions and some functions in klarkc/purs-eval#3

Start by reviewing how the client is currently organized and compare the requested reuse of its type definitions and functions with the needs described in klarkc/purs-eval#3. Define what publishing the client as a library must expose and verify that those definitions and functions are usable by consumers.