Enhancements to run_command

[ChrisYounger]

Desired features:

• Streaming output back to the console before completion
• ability to cancel job
• timeout that cancels job and all children

Might be useful reading: https://stackoverflow.com/questions/323972/is-there-any-way-to-kill-a-thread https://stackoverflow.com/questions/1191374/using-module-subprocess-with-timeout