Let dwarfdump functions write to an arbitrary Write object, and buffer stdout
Let dwarfdump functions write to an arbitrary Write object, and buffer stdout

Before this change, every print(ln) was taking a lock, doing a write syscall,
and releasing the lock.

Before:

time ( target/release/examples/dwarfdump -i ~/mozilla-central/obj-ff-opt/dist/bin/libxul.so >& /dev/null )
real	8m25.647s
user	7m6.523s
sys	1m18.650s

After:

time ( target/release/examples/dwarfdump -i ~/mozilla-central/obj-ff-opt/dist/bin/libxul.so >& /dev/null )
real	3m35.072s
user	3m33.297s
sys	0m1.556s

gimli-rs/gimli,gimli-rs/gimli