Refactor api-promise/rx (#566)

* Use a generic abstract OnCall

* Add OnCall for Promise

* First run at fixing extrinsics

* Fix types

* Make submittable extrinsic work

* Move file

* Make derive work

* Fix types

* Only call metadata once

* Make tests pass

* Put event emitter in apirx

* Fix small bugs

* Fix tests

* Fix bug decorateStorage

* Make tests pass for tx

* Move rpc base to apirx

* Fix lint

* Fix small bugs

* Fix bug with isSubscription

* Fix codeclimate

* Revert

* Add tslint disable line

* Fix lint

* Skip e2e

* Typo

* Lint

* Re-add combinator back

* Add ._rx in Base

* Make extrinsics work

* Update derivex

* Fix bug lint

* Fix circular dep

* Fix bug e2e

* Remove useless check

* Add description comment

* Clean stuff

* Move assert to Base

* Bump version, update CHANGELOG

* Make _rx private

* Private emit

packages/type-jsonrpc/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@polkadot/jsonrpc",
-  "version": "0.39.12",
+  "version": "0.40.0",
   "description": "Method definitions for the Polkadot RPC layer",
   "main": "index.js",
   "engines": {