[Process] Renamed ProcessOutput->ProcessReader, allow Process.run(&writable)
[Process] Renamed ProcessOutput->ProcessReader, allow Process.run(&writable)

- ProcessOutput had a property output_string, which was overuse of the word "output".
- Renamed to ProcessResult.
- Can Process.run() with the &writable flag to pipe through input.
- Useful for running buggy programs that close if stdin is closed.

Plasmaworks/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue,AbePralle/Rogue,AbePralle/Rogue,Plasmaworks/Rogue