Add keypair & update pubkey

Keypair & FullKeypair match structs in damus ios

Signed-off-by: kernelkind <kernelkind@gmail.com>
Signed-off-by: William Casarin <jb55@jb55.com>

enostr/src/lib.rs

@@ -2,6 +2,7 @@ mod client;
 mod error;
 mod event;
 mod filter;
+mod keypair;
 mod profile;
 mod pubkey;
 mod relay;
@@ -11,6 +12,8 @@ pub use error::Error;
 pub use event::{Event, EventId};
 pub use ewebsock;
 pub use filter::Filter;
+pub use keypair::{FullKeypair, Keypair};
+pub use nostr::SecretKey;
 pub use profile::Profile;
 pub use pubkey::Pubkey;
 pub use relay::message::{RelayEvent, RelayMessage};