feature request: show errors in red #129

Considering all the output pius users have to see and how the process can mentally put someone into an autopilot state, errors can easily go unnoticed. There's also a natural tendency to focus on the next prompt. And also since there is no other mechanism ATM for recording failures it's somewhat important that errors be seen. I suggest highlighting errors in red, or making them blink, or something. It should be done in a way that doesn't produce junk on non-color terminals (e.g. when the output is streamed to a text file). In zsh there's a simple test to check if the terminal is color.. not sure about python.