IMPORTANT: usage change, no works similarly to strip.

IMPORTANT: usage change, no works similarly to strip.
dwz file
will modify file in place (well, write to temporary, rename over),
dwz -o outfile file
will do what dwz file outfile did before.
dwz file1 file2 file3
will modify all the files in place,
dwz
will modify a.out in place,
dwz -o b.out
will modify a.out into b.out.

In addition to that this change revamps the OOM handling to just
not handle the single currently handled file, complain,
cleanup all memory and continue with the next file.