Merge latest master in v0.2.0

eth2/utils/bls/src/aggregate_signature.rs

@@ -32,9 +32,12 @@ impl AggregateSignature {
 
     /// Add (aggregate) a signature to the `AggregateSignature`.
     pub fn add(&mut self, signature: &Signature) {
-        if !self.is_empty {
-            self.aggregate_signature.add(signature.as_raw())
+        if self.is_empty {
+            self.aggregate_signature = RawAggregateSignature::new();
+            self.is_empty = false;
         }
+
+        self.aggregate_signature.add(signature.as_raw())
     }
 
     /// Add (aggregate) another `AggregateSignature`.

eth2/utils/bls/src/fake_aggregate_public_key.rs

@@ -22,6 +22,13 @@ impl FakeAggregatePublicKey {
         Self::zero()
     }
 
+    pub fn empty_signature() -> Self {
+        Self {
+            bytes: vec![0; BLS_PUBLIC_KEY_BYTE_SIZE],
+            point: G1Point::new(),
+        }
+    }
+
     pub fn from_bytes(bytes: &[u8]) -> Result<Self, DecodeError> {
         if bytes.len() != BLS_PUBLIC_KEY_BYTE_SIZE {
             Err(DecodeError::InvalidByteLength {