Update Maven dependencies and plugins

The updated Netty-socketio adds compatibility with
socket.io-client >= 1.3.

pom.xml

@@ -8,7 +8,7 @@
 
 	<properties>
 		<org.springframework-version>4.0.9.RELEASE</org.springframework-version>
-		<org.springframework.security-version>3.2.5.RELEASE</org.springframework.security-version>
+		<org.springframework.security-version>3.2.6.RELEASE</org.springframework.security-version>
 		<org.springframework.integration-mail-version>4.0.6.RELEASE</org.springframework.integration-mail-version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<project.url>https://scm.thm.de/arsnova</project.url>
@@ -95,7 +95,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-javadoc-plugin</artifactId>
-				<version>2.10.1</version>
+				<version>2.10.2</version>
 				<configuration></configuration>
 			</plugin>
 		</plugins>
@@ -261,7 +261,7 @@
 		<dependency>
 			<groupId>com.corundumstudio.socketio</groupId>
 			<artifactId>netty-socketio</artifactId>
-			<version>1.7.6</version>
+			<version>1.7.7</version>
 		</dependency>
 		<dependency>
 			<groupId>javax.inject</groupId>
@@ -350,7 +350,7 @@
 			<plugin>
 				<groupId>org.eclipse.jetty</groupId>
 				<artifactId>jetty-maven-plugin</artifactId>
-				<version>9.2.7.v20150116</version>
+				<version>9.2.10.v20150310</version>
 				<configuration>
 					<scanIntervalSeconds>1</scanIntervalSeconds>
 					<webApp>
@@ -389,7 +389,7 @@
 			<plugin>
 				<groupId>org.jacoco</groupId>
 				<artifactId>jacoco-maven-plugin</artifactId>
-				<version>0.7.2.201409121644</version>
+				<version>0.7.4.201502262128</version>
 				<executions>
 					<execution>
 						<id>default-prepare-agent</id>
@@ -414,7 +414,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-checkstyle-plugin</artifactId>
-				<version>2.13</version>
+				<version>2.14</version>
 				<configuration>
 					<configLocation>ARSnova-checkstyle-checker.xml</configLocation>
 				</configuration>