Major classes, variables and strings refactoring. Code cleanup.

app/src/main/res/drawable/ic_filter.xml

@@ -5,5 +5,5 @@
     android:viewportHeight="24.0">
     <path
         android:fillColor="#C0C0C0"
-        android:pathData="M12,8c1.1,0 2,-0.9 2,-2s-0.9,-2 -2,-2 -2,0.9 -2,2 0.9,2 2,2zM12,10c-1.1,0 -2,0.9 -2,2s0.9,2 2,2 2,-0.9 2,-2 -0.9,-2 -2,-2zM12,16c-1.1,0 -2,0.9 -2,2s0.9,2 2,2 2,-0.9 2,-2 -0.9,-2 -2,-2z" />
+        android:pathData="M10,18h4v-2h-4v2zM3,6v2h18L21,6L3,6zM6,13h12v-2L6,11v2z" />
 </vector>

app/src/main/res/drawable/splash_drawable.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <layer-list xmlns:android="http://schemas.android.com/apk/res/android"
     android:opacity="opaque">
-    <item android:drawable="@color/darkOnLight" />
+    <item android:drawable="@drawable/launcher_background" />
     <item
         android:width="240dp"
         android:height="240dp"