Enforce Java5 compilation

Author: shirish87

pom.xml

@@ -13,13 +13,27 @@
     <properties>
         <unirest.version>1.4.9</unirest.version>
         <httpclient.version>4.5.2</httpclient.version>
-        <jackson.version>2.2.0</jackson.version>
+        <jackson.version>2.1.0</jackson.version>
         <junit.version>4.12</junit.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>1.5</maven.compiler.source>
         <maven.compiler.target>1.5</maven.compiler.target>
     </properties>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.5.1</version>
+                <configuration>
+                    <source>1.5</source>
+                    <target>1.5</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
     <dependencies>
         <dependency>
             <groupId>com.google.http-client</groupId>