calculate dimensions in metrics constructor

squarenotsquare/src/themes/Metrics.js

@@ -14,16 +14,20 @@ class AppMetrics {
       this.screenWidth = width;
       this.screenHeight = height;
     }
+
+    this.screenSections = {
+      headerHeight: this.normalize(20),
+      sectionWidth: this.screenWidth
+    }
+  
+    this.icons = {
+      splashIcon: this.normalize(100)
+    }
   }
 
   normalize(size){
     return (size * this.scalar);
   }
-
-  screenSections = {
-    headerHeight: this.normalize(20),
-    sectionWidth: this.screenWidth
-  }
 }
 
 const Metrics = new AppMetrics();