QR-code icons + class update + sass update

src/sass/main.scss

@@ -5,6 +5,7 @@
 @import "icons";
 @import "buttons";
 @import "forms";
+@import "qr";
 @import "mixins/mixins";
 @import "views/views";
 @import "directives/directives";

src/sass/qr.scss

@@ -0,0 +1,20 @@
+qrcode {
+  &.qr-icon {
+    &::before {
+      content: "";
+      background-size: 100% 100%;
+      display: block;
+      margin-left: calc(50% - 22px);
+      margin-top: 88px;
+      width: 44px;
+      height: 44px;
+      position: absolute;
+    }
+    &--bch::before {
+      background-image: url('../img/icon-qr-bch.png');
+    }
+    &--btc::before {
+      background-image: url('../img/icon-qr-btc.png');
+    }
+  }
+}

www/views/tab-receive.html

@@ -41,7 +41,7 @@
               </button>
             </span>
 
-            <qrcode ng-if="addr" size="220" data="{{ protocolHandler }}:{{addr}}" color="#334"></qrcode>
+            <qrcode class="qr-icon qr-icon--{{ wallet.coin }}" ng-if="addr" size="220" data="{{ protocolHandler }}:{{addr}}" color="#334"></qrcode>
             <div class="address-label">
               <span class="ellipsis">{{addr}}</span>
               <ion-spinner ng-show="!addr" class="spinner-dark" icon="crescent"></ion-spinner>