Add examples and refactor code

Add examples and refactor code

Example/examples/Polygon.js

@@ -0,0 +1,83 @@
+import React, {
+    Component
+} from 'react-native';
+
+import Svg, {
+    Polygon,
+    Group
+} from 'react-native-art-svg';
+
+class PolygonExample extends Component{
+    static title = 'The following example creates a polygon with three sides';
+    render() {
+        return <Svg
+            height="100"
+            width="100"
+        >
+            <Polygon
+                points="40,5 70,80 25,95"
+                fill="lime"
+                stroke="purple"
+                strokeWidth="1"
+            />
+        </Svg>;
+    }
+}
+
+
+class FourSidePolygon extends Component{
+    static title = 'The following example creates a polygon with four sides';
+    render() {
+        return <Svg
+            height="100"
+            width="100"
+        >
+            <Polygon
+                points="70,5 90,75 45,90 25,80"
+                fill="lime"
+                stroke="purple"
+                strokeWidth="1"
+            />
+        </Svg>;
+    }
+}
+
+class StrarPolygon extends Component{
+    static title = 'Use the <Polygon /> element to create a star';
+    render() {
+        return <Svg
+            height="105"
+            width="105"
+        >
+            <Group scale="0.5">
+                <Polygon
+                    points="100,10 40,198 190,78 10,78 160,198"
+                    fill="lime"
+                    stroke="purple"
+                    strokeWidth="5"
+                />
+            </Group>
+        </Svg>;
+    }
+}
+
+const icon = <Svg
+    height="20"
+    width="20"
+>
+    <Group scale="0.1">
+        <Polygon
+            points="100,10 40,198 190,78 10,78 160,198"
+            fill="lime"
+            stroke="purple"
+            strokeWidth="10"
+        />
+    </Group>
+</Svg>;
+
+const samples = [PolygonExample, FourSidePolygon, StrarPolygon];
+
+export {
+    icon,
+    samples
+}