Implement new API for sign_and_submit_then_watch (#354)

* WIP Implementing new event subscription API

* back to lifetimes, fix example

* no more need for accept_weak_inclusion

* thread lifetime through to prevent 'temporary dropped' issue

* make working with events a little nicer

* Get tests compiling

* fmt and clippy

* _name back to name

* dont take ownership, just have stronger note

* Attempt to fix test

* remove commented-out code

* Add a couple more helper methods and a test

* Remove custom ExtrinsicFailed handling; treat them like other events

* Handle runtime errors in TransactionProgress related bits

* cargo fmt + clippy

* Fix some of the failing tests

* remove unused import

* fix transfer_error test

* Fix compile errors against new substrate latest

* Comment tweaks, and force test-runtime rebuild

* Drop the TransactionProgress subscription when we hit 'end' statuses

* cargo fmt

* find_event to find_first_event and helper to return all matching events

* TransactionProgressStatus to TransactionStatus

* Copy and improve docs on TransactionStatus from substrate

* debug impl for Client to avoid manual debug impls elsewhere

* Add and tweak comments, specifically a note about block inclusion on errors

* clippy + fmt

* Fix docs

* Ignore 'error' statuses and adhere to the substrate docs

* tweak and improve some comments per @dvdplm's suggestions

* Break transaction* structs into separate file

* fmt and fix doc link

codegen/src/ir.rs

@@ -72,6 +72,7 @@ impl ItemMod {
     }
 }
 
+#[allow(clippy::large_enum_variant)]
 #[derive(Debug, PartialEq, Eq)]
 #[allow(clippy::large_enum_variant)]
 pub enum Item {