Add writecb to try and get it to maybe actually make some output this time.
See if draining the input helps.
Try watermarks.
Other way around.
Change callbacks, set watermark, and free in writecb.
Make everything visible from readcb
Use evbuffer_add_file again.
Remove debugging.
gopher no longer uses hexdump.o; clean up Makefile, too.
Fix hexdump-echo
Really fix hexdump-echo