Return error code or process object from subprocess functions

[stevekm]

Right now when Python subprocess is used to execute a shell command, nothing is typically returned.

Might be good to always return the error code, or the SubprocessCmd or process object completely. This would be good for error checking within the script to make sure the commands finished successfully

reference: https://github.com/NYU-Molecular-Pathology/util/blob/master/tools.py#L22