ecdsa: do not abort on compressed pubkeys

implement ecdsa key support

rename keytype to keyformat and introduce enum

Since the RFC also names it key format.

net::ssh: update stdlib changes

remove unused dependency

harden against "compromise via lattices"

make write functions return number of bytes written

update to latest stdlib changes

fixes to work with latest hare updates

memio changes i've missed

update to os::signal changes

s/SIZE/SZ

update to memio

fix uninitialized values

This is a dirty fix to make it compile until a better solution/pattern
is found.

rsa: fix clearing privkey params on decode

export ssh::format::newkey

format::ssh: close base64 encoder at right moment

otherwise the padding will be written after the comment.

format::ssh: add rsa key support

Updates per crypto::aes changes

format::ssh: factor out newkey, free keys on err