Move the final output to stdout, and add some labels

Now the useful output is all on stdout, and stderr only has debugging
stuff. I really should remove some of that - or at least only print it
in a 'verbose' mode.
print debug out only when DEBUG is set
Merge pull request #4 from JonnyJD/no_debug_out

print debug out only when DEBUG is set
Merge branch 'master' into isrcs

This merges the DEBUG flag and outputs relevant information on stdout,
rather than stderr.

Conflicts:
	image_id.c