Add Alice execution path

Consolidate and simplify swap execution. Generators are no longer
needed. Consolidate recovery and swap data structures. The
recursive calls can be replaced with a loop if returning prior to
completion is desired for testing purposes.

Fill out alice abort path

Move state machine executors into seperate files

Not compiling due to recursion/async issues

Fix async recursion compilation errors

Fix Bob swap execution

Remove check for ack message from Alice. Seems like a bad idea to
rely on an acknowledgement message instead of looking at the
blockchain.

Fix Bob abort

Fix warnings

Xmr lock complete

Add TxCancel submit to XmrLocked

Bob swap completed

Remove alice

xmr-btc/src/bitcoin.rs

@@ -186,6 +186,11 @@ pub trait WatchForRawTransaction {
     async fn watch_for_raw_transaction(&self, txid: Txid) -> Transaction;
 }
 
+#[async_trait]
+pub trait GetRawTransaction {
+    async fn get_raw_transaction(&self, txid: Txid) -> Result<Transaction>;
+}
+
 #[async_trait]
 pub trait BlockHeight {
     async fn block_height(&self) -> u32;