State cache and other performance optimizations (#1345)

* State caching

* Better code caching

* Execution optimizaton

* More optimizations

* Updated wasmi

* Caching test

* Style

* Style

* Reverted some minor changes

* Style and typos

* Style and typos

* Removed panics on missing memory

substrate/core/executor/src/lib.rs

@@ -44,9 +44,6 @@ extern crate parking_lot;
 #[macro_use]
 extern crate log;
 
-#[macro_use]
-extern crate lazy_static;
-
 #[macro_use]
 extern crate error_chain;
 
@@ -84,7 +81,5 @@ pub trait RuntimeInfo {
 	fn runtime_version<E: Externalities<Blake2Hasher>> (
 		&self,
 		ext: &mut E,
-		heap_pages: usize,
-		code: &[u8]
 	) -> Option<RuntimeVersion>;
 }