Improve the image editor.

A variety of improvements to the image editor, such as:

- New, fullscreen styling
- Smoother lines
- Better text and sticker handling
- Improved color picker with a history pallette
- New highlighter tool

res/layout/item_color.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:padding="6dp">
+
+    <ImageView
+        android:layout_width="20dp"
+        android:layout_height="20dp"
+        android:src="@drawable/circle_white"/>
+
+    <ImageView
+        android:id="@+id/palette_item_foreground"
+        android:layout_width="16dp"
+        android:layout_height="16dp"
+        android:src="@drawable/circle_white"
+        android:layout_gravity="center"
+        tools:tint="@color/red"/>
+
+</FrameLayout>