Split subxt (#102)

* Proc macro improvements.

* Use proc-macros.

* Update examples.

* Fix build.

* Run rustfmt.

* Fix total issuance test.

* Remove gas limit from put code call.

* Handle runtime errors.

* Fix tests.

* Make test more reliable.

* Revert "Handle runtime errors."

This reverts commit 26f30a9f4cfcfddfb3e49308cded46cfe6468697.

* Use expect instead of unwrap.

* Parse marker type.

* Fetch doesn't fail.

examples/submit_and_watch.rs

@@ -16,8 +16,9 @@
 
 use sp_keyring::AccountKeyring;
 use substrate_subxt::{
-    balances,
-    DefaultNodeRuntime as Runtime,
+    balances::*,
+    ClientBuilder,
+    DefaultNodeRuntime,
 };
 
 #[async_std::main]
@@ -27,18 +28,15 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let signer = AccountKeyring::Alice.pair();
     let dest = AccountKeyring::Bob.to_account_id().into();
 
-    let cli = substrate_subxt::ClientBuilder::<Runtime>::new()
-        .build()
-        .await?;
-    let xt = cli.xt(signer, None).await?;
-    let xt_result = xt
+    let client = ClientBuilder::<DefaultNodeRuntime>::new().build().await?;
+    let result = client
+        .xt(signer, None)
+        .await?
         .watch()
-        .submit(balances::TransferCall {
-            to: &dest,
-            amount: 10_000,
-        })
+        .transfer(&dest, 10_000)
         .await?;
-    if let Some(event) = xt_result.find_event::<balances::TransferEvent<_>>()? {
+
+    if let Some(event) = result.transfer()? {
         println!("Balance transfer success: value: {:?}", event.amount);
     } else {
         println!("Failed to find Balances::Transfer Event");