EIP-86 (#4697)

* EIP-86

* Disable EIP-86 auto activation for now

ethcore/light/src/client/mod.rs

@@ -106,6 +106,9 @@ pub trait LightChainClient: Send + Sync {
 
 	/// Get the `i`th CHT root.
 	fn cht_root(&self, i: usize) -> Option<H256>;
+
+	/// Get the EIP-86 transition block number.
+	fn eip86_transition(&self) -> u64;
 }
 
 /// Something which can be treated as a `LightChainClient`.
@@ -384,4 +387,8 @@ impl LightChainClient for Client {
 	fn cht_root(&self, i: usize) -> Option<H256> {
 		Client::cht_root(self, i)
 	}
+
+	fn eip86_transition(&self) -> u64 {
+		self.engine().params().eip86_transition
+	}
 }