remove unused clean from makefile

split make and make install

update install instructions, dependencies

make minor adjustments to readme

update install instructions, add man page

remove pledge, unveil for edit for arbitrary editors

correct add-user example

bump version to v1.8.1

add mailing list info to readme

correct security description in readme

fix cold start shh migration bug

fix padding oracle capitalization in readme

switch to aes-gcm, add version .shh file

add documentation for .shhconfig

add support for project-level config file

bump version to v1.6.3

output useful error instead of panic

update module path

use openbsd isc license

write errors to stderr

fix readme example alignment