Change get_balance to return in categories.

Add type balance with add, display traits. Change affected tests.
Update `CHANGELOG.md`

Author: wszdexdrf

CHANGELOG.md

@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 - Fee sniping discouraging through nLockTime - if the user specifies a `current_height`, we use that as a nlocktime, otherwise we use the last sync height (or 0 if we never synced)
+- Return balance in separate categories, namely `available`, `trusted_pending`, `untrusted_pending` & `immature`.  
 
 ## [v0.19.0] - [v0.18.0]
 

src/blockchain/electrum.rs

@@ -383,6 +383,6 @@ mod test {
             .sync_wallet(&wallet, None, Default::default())
             .unwrap();
 
-        assert_eq!(wallet.get_balance().unwrap(), 50_000);
+        assert_eq!(wallet.get_balance().unwrap().untrusted_pending, 50_000);
     }
 }

src/blockchain/mod.rs

@@ -187,7 +187,7 @@ This example shows how to sync multiple walles and return the sum of their balan
 # use bdk::database::*;
 # use bdk::wallet::*;
 # use bdk::*;
-fn sum_of_balances<B: BlockchainFactory>(blockchain_factory: B, wallets: &[Wallet<MemoryDatabase>]) -> Result<u64, Error> {
+fn sum_of_balances<B: BlockchainFactory>(blockchain_factory: B, wallets: &[Wallet<MemoryDatabase>]) -> Result<Balance, Error> {
     Ok(wallets
         .iter()
         .map(|w| -> Result<_, Error> {