Review use of Debug formatting and avoid in release-mode logging

[kinetiknz]

Related to issue #139, @bholley is working on reducing Debug trait use in release builds (for code size reasons). He proposed:

what we do in stylo is use debug! and trace! for stuff where we need/want :?, and then avoid :? in info/warn/log which are compiled in release builds

So we'll need to review existing log! use and replace with debug!/trace! as necessary and remove any use of :? inside log!.

[rillian]

This should be addressed for mp4parse now. Thanks for filing!

[bholley]

Thanks for fixing!