Skip EncryptorsTests when using <JDK 1.6 as AES isn't available

crypto/crypto.gradle

@@ -1,5 +1,10 @@
 // crypto module build file
 
-dependencies {
+jdkVersion = System.properties['java.version']
+isJdk6 = jdkVersion >= '1.6'
 
+test {
+    if (!isJdk6) {
+        exclude '**/EncryptorsTests.class'
+    }
 }