Remove use of org.json

This commit removes all use of org.json in production code and moves
the json api to a test only dependency.

Closes gh-507

pom.xml

@@ -92,6 +92,11 @@
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
+			<dependency>
+				<groupId>com.vaadin.external.google</groupId>
+				<artifactId>android-json</artifactId>
+				<version>0.0.20131108.vaadin1</version>
+			</dependency>
 			<dependency>
 				<groupId>xmlunit</groupId>
 				<artifactId>xmlunit</artifactId>