ci: add rust build to ci (William Casarin)

rust: build secp256k1 as a part of the build process (William Casarin)

rust: generate rust bindings from C header (William Casarin)

cursor: fix warning that build.rs is complaining about (William Casarin)

api: don't expose many internals, like note (William Casarin)

stream: actually use file pointer in stream api (William Casarin)

add "import -" (Yasuhiro Matsumoto)

build: fix additional compiler errors (William Casarin)

lmdb: don't begin query if we have a bad lmdb env (William Casarin)

cursor: silence utf8 warnings (William Casarin)

cursor: sync with damus' cursor (William Casarin)

pushed to nostrdb:refs/heads/master

http://git.jb55.com/nostrdb/commit/a0b7f76e59afa5662585fcd6ee2d7a8760d51fb0.html