Nicer display output for hash types.

src/hash.rs

@@ -206,7 +206,10 @@ macro_rules! impl_hash {
 		}
 		impl fmt::Display for $from {
 			fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-				(self as &fmt::Debug).fmt(f)
+				for i in self.0[0..3].iter() {
+					try!(write!(f, "{:02x}", i));
+				}
+				write!(f, "…{:02x}", self.0.last().unwrap())
 			}
 		}
 

src/json_aid.rs

@@ -35,6 +35,10 @@ pub fn h256_from_json(json: &Json) -> H256 {
 	}
 }
 
+pub fn vec_h256_from_json(json: &Json) -> Vec<H256> {
+	json.as_array().unwrap().iter().map(&h256_from_json).collect()
+}
+
 pub fn u256_from_str(s: &str) -> U256 {
 	if s.len() >= 2 && &s[0..2] == "0x" {
 		U256::from_str(&s[2..]).unwrap_or(U256::from(0))