VM tracing and JSON RPC endpoint for it. (#1169)

* Groundwork for basic VM tracing.

* RPC endpoint for VM tracing and ser/de types ready.

* Create VMTracer trait.

* Rearchitected VM tracing to reflect existing tracing.

Should more or less work now.

* Integrated VM tracing into JSONRPC.

* Fix ethcore module tests.

* Add tests for VM tracing.

* Fix consensus test code.

* Fix mock tests.

* Added VM trace information for post-execution stuff.

* Fix max-value calls and add "creates" field to getTransaction.

* Tests for VM tracing.

* Don't implement the trait with unimplemented.

* Remove invlaid comment.

* Fix tests.

json/src/state/transaction.rs

@@ -40,7 +40,7 @@ pub struct Transaction {
 	/// To.
 	pub to: MaybeEmpty<Address>,
 	/// Value.
-	pub value: Uint
+	pub value: Uint,
 }
 
 #[cfg(test)]