Made ecrecover implementation trait public (#11188)

* Made ecrecover Implementation trait public

* Make all builtin contract types public

This ensure the API is consistent in terms of visibility.

ethcore/builtin/src/lib.rs

@@ -39,7 +39,7 @@ use parity_bytes::BytesRef;
 use parity_crypto::digest;
 
 /// Native implementation of a built-in contract.
-trait Implementation: Send + Sync {
+pub trait Implementation: Send + Sync {
 	/// execute this built-in on the given input, writing to the given output.
 	fn execute(&self, input: &[u8], output: &mut BytesRef) -> Result<(), &'static str>;
 }
@@ -359,31 +359,31 @@ impl Implementation for EthereumBuiltin {
 }
 
 #[derive(Debug)]
-struct Identity;
+pub struct Identity;
 
 #[derive(Debug)]
-struct EcRecover;
+pub struct EcRecover;
 
 #[derive(Debug)]
-struct Sha256;
+pub struct Sha256;
 
 #[derive(Debug)]
-struct Ripemd160;
+pub struct Ripemd160;
 
 #[derive(Debug)]
-struct Modexp;
+pub struct Modexp;
 
 #[derive(Debug)]
-struct Bn128Add;
+pub struct Bn128Add;
 
 #[derive(Debug)]
-struct Bn128Mul;
+pub struct Bn128Mul;
 
 #[derive(Debug)]
-struct Bn128Pairing;
+pub struct Bn128Pairing;
 
 #[derive(Debug)]
-struct Blake2F;
+pub struct Blake2F;
 
 impl Implementation for Identity {
 	fn execute(&self, input: &[u8], output: &mut BytesRef) -> Result<(), &'static str> {