Update XML schema definitions for Spring configuration

Removed unused schemas and updated the remaining for Spring 4.1.

src/main/webapp/WEB-INF/spring/arsnova-servlet.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xmlns:aop="http://www.springframework.org/schema/aop"
-	xmlns:mvc="http://www.springframework.org/schema/mvc"
 	xmlns:context="http://www.springframework.org/schema/context"
+	xmlns:mvc="http://www.springframework.org/schema/mvc"
 	xmlns:p="http://www.springframework.org/schema/p"
-	xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
-		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
-		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
-		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
+	xsi:schemaLocation="
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
+		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
+		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
 
 	<!-- ARSnova Servlet Context -->
 

src/main/webapp/WEB-INF/spring/spring-main.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
-	xmlns:p="http://www.springframework.org/schema/p" xmlns:util="http://www.springframework.org/schema/util"
-	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:task="http://www.springframework.org/schema/task"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xmlns:aop="http://www.springframework.org/schema/aop"
-	xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
-		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
-		http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.0.xsd
-		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
-		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd
-		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
+	xmlns:context="http://www.springframework.org/schema/context"
+	xmlns:task="http://www.springframework.org/schema/task"
+	xmlns:p="http://www.springframework.org/schema/p"
+	xsi:schemaLocation="
+		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
+		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
+		http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.1.xsd">
 
 	<bean id="propertyPlaceholderConfigurer"
 		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"