Quietly collect debug logs.

[jdeanwallace]

Don't print any status/info messages to stdout when running the collect-debug-logs script in -q silent mode.

Design Decisions

1. Added a helper function, print_info, that prints to stdout only when collect-debug-logs is in silent mode.
2. The helper function wraps printf and not echo in order to have more flexibility when wanting to print special characters (i.e newlines). The caveats include:
   1. You always need to add a newline to the end of each status/info message.
   2. Watchout when printing --, which has a special meaning for printf (i.e ignore everything after --).

Demo video.

Reverts #100 and Fixes #106

[mtlynch]

LGTM, thanks!