update source level from java 1.6 to 1.7 in the project.

bindings/java/nbproject/project.xml

@@ -116,7 +116,7 @@
                 <package-root>src</package-root>
                 <classpath mode="compile">lib;lib/diffutils-1.2.1.jar;lib/sqlite-jdbc-3.7.8-SNAPSHOT.jar;lib/junit-4.8.2.jar</classpath>
                 <built-to>build</built-to>
-                <source-level>1.6</source-level>
+                <source-level>1.7</source-level>
             </compilation-unit>
             <compilation-unit>
                 <package-root>test</package-root>
@@ -124,7 +124,7 @@
                 <classpath mode="compile">build;lib/diffutils-1.2.1.jar;lib/diffutils-1.2.1-javadoc.jar;lib/diffutils-1.2.1-sources.jar;lib/junit-4.8.2.jar</classpath>
                 <built-to>build</built-to>
                 <built-to>test</built-to>
-                <source-level>1.6</source-level>
+                <source-level>1.7</source-level>
             </compilation-unit>
         </java-data>
         <preferences xmlns="http://www.netbeans.org/ns/auxiliary-configuration-preferences/1">