This library provides the ability to launch and interact with external
processes. It wraps around the process library, and intends to improve
upon it by:

1. Using type variables to represent the standard streams, making them
   easier to manipulate

2. Use proper concurrency (e.g., the async library) in place of the
   weird lazy I/O tricks for such things as consuming output streams

3. Allow for more complex concurrency by providing STM-based functions

4. Using binary I/O correctly

5. Providing a more composable API, designed to be easy to use for
   both simple and complex use cases