add install-local target

clarify the license, or the lack of thereof

update changelog

drop now unused xmalloc()

use xcalloc insntead of xmalloc; avoids mul overflow

use strlcat/strlcpy instead of strcat/strcpy while here introduce also xasprintf and xstrdup to avoid some malloc+strcpy sequences.

pledge earlier

usage() on unknown flags

move usage to separate function

enable debugging will (hopefully) remember to turn it off again before tagging a release.

fix readme

kill unused variables

add opener and marking functions

bind e to cmd_edit

bind v to cmd_view