Backports to beta (#2068)

* Fix several RPCs (#1926)

* Fix up pending receipts details.

* Add support for additional params and registry over RPC.

* Fix tests.

* Add test, additional fix.

Fixes #1932.

* Fix up tests.

* Fix test.

* Fix test.

* DB WAL size limit (#1935)

* Limit WAL size

* Check pruning by db modification date (#1924)

* Cache address hash (#1943)

* ECIES without MAC (#1948)

* Use random IV for ECIES AES

* ECIES encrypt/decrypt for a single message

* Derive IV from shared secret

* Apply settings to column families

* fixed #1933 (#1979)

* Fixed neighbours collection (#1996)

* dapps-hosts configuration

* Disabled counter check

* always process trie death row on commit, add more tracing

* fixed transaction addresses mapping, fixes #1971

* simplified iterator

* v1.3.1

* v1.3.1

ethcore/src/engines/mod.rs

@@ -44,6 +44,9 @@ pub trait Engine : Sync + Send {
 	/// Additional engine-specific information for the user/developer concerning `header`.
 	fn extra_info(&self, _header: &Header) -> HashMap<String, String> { HashMap::new() }
 
+	/// Additional information.
+	fn additional_params(&self) -> HashMap<String, String> { HashMap::new() } 
+
 	/// Get the general parameters of the chain.
 	fn params(&self) -> &CommonParams;