nostrdb: add initial swift integration (William Casarin)

c: add nostrdb c lib (William Casarin)

c: add jsmn json parser (William Casarin)

c: add new cursor util (William Casarin)

c: add copy nostrdb devtool (William Casarin)

c: update protoverse_cursor to jb55_cursor (William Casarin)

test: add my contact list for as json parsing test data (William Casarin)

event: separate logic from data using extensions (William Casarin)

pushed to refs/heads/master

http://git.jb55.com/damus/commit/61051ee853410c0e26be9441bcce2f446d39ba19.html