Breaking change to modify the stderr, stdout, and output members of ProcessRunnerResult so that they return pre-decoded Strings instead of List<int>s. Added stderrRaw, stdoutRaw, and outputRaw members that return the original List<int> values. Decoded strings are decoded by a new decoder optional argument which uses SystemEncoder by default.

Breaking change to modify the stdin member of WorkerJob so that it is a Stream<String> instead of Stream<List<int>>, and a new stdinRaw method that is a Stream<List<int>>. Added an encoder attribute to ProcessRunner that provides the encoding for the stdin stream, as well as the default decoding for results.

Added ProcessPool.runToCompletion convenience function to provide a simple interface that just delivers the final results, without dealing with streams.

Added more tests.