Monero: fix decoy selection algo and add test for latest spendable (#384)

* Monero: fix decoy selection algo and add test for latest spendable

- DSA only selected coinbase outputs and didn't match the wallet2
implementation
- Added test to make sure DSA will select a decoy output from the
most recent unlocked block
- Made usage of "height" in DSA consistent with other usage of
"height" in Monero code (height == num blocks in chain)
- Rely on monerod RPC response for output's unlocked status

* xmr runner tests mine until outputs are unlocked

* fingerprintable canoncial select decoys

* Separate fingerprintable canonical function

Makes it simpler for callers who are unconcered with consistent
canonical output selection across multiple clients to rely on
the simpler Decoy::select and not worry about fingerprintable
canonical

* fix merge conflicts

* Put back TODO for issue #104

* Fix incorrect check on distribution len

The RingCT distribution on mainnet doesn't start until well after
genesis, so the distribution length is expected to be < height.

To be clear, this was my mistake from this series of changes
to the DSA. I noticed this mistake because the DSA would error
when running on mainnet.

tests/processor/src/networks.rs

@@ -308,11 +308,11 @@ impl Wallet {
               .expect("prior transaction was never published"),
           );
         }
-        let mut decoys = Decoys::select(
+        let mut decoys = Decoys::fingerprintable_canonical_select(
           &mut OsRng,
           &rpc,
           Protocol::v16.ring_len(),
-          rpc.get_height().await.unwrap() - 1,
+          rpc.get_height().await.unwrap(),
           &these_inputs,
         )
         .await