Update of the default placeholder for wallets.

Trust/Accounts/ViewModels/AccountViewModel.swift

@@ -17,7 +17,7 @@ struct AccountViewModel {
         return wallet.type == .watch(wallet.address)
     }
     var balance: String {
-        return walletBalance?.amountFull ?? "0"
+        return walletBalance?.amountFull ?? "--"
     }
     var title: String {
         return wallet.address.description

Trust/Accounts/Views/AccountViewCell.xib

@@ -42,7 +42,7 @@
                             <stackView opaque="NO" contentMode="scaleToFill" distribution="fillProportionally" alignment="center" spacing="10" translatesAutoresizingMaskIntoConstraints="NO" id="wMR-ps-QHM">
                                 <rect key="frame" x="249" y="19" width="49" height="22"/>
                                 <subviews>
-                                    <imageView userInteractionEnabled="NO" contentMode="scaleToFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="glasses" translatesAutoresizingMaskIntoConstraints="NO" id="mbU-gV-kxo">
+                                    <imageView userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="glasses" translatesAutoresizingMaskIntoConstraints="NO" id="mbU-gV-kxo">
                                         <rect key="frame" x="0.0" y="2" width="18" height="18"/>
                                         <color key="tintColor" white="0.0" alpha="1" colorSpace="calibratedWhite"/>
                                         <constraints>