Build script for poplog command-tool does not handle 'funny' characters

[sfkleach]

If the values of environment variables contain anything other than plain text on a single line, things can go wrong.

• Newlines are not handled properly
• Non-printing characters are not handled properly
• Backslashes are not handled properly (I will solve this one)

This is parked as tech debt because:

• We will sort it out when we transform makePoplogCommander.sh into a Python script and we can see that coming.
• There are no plausible circumstances under which any Poplog environment variable contains a newline.
• It's not cheap to solve and not an active issue.