stripped support: implement has_secret support, in ui and impot of secret keys

Closes #570

libraries/spongycastle/pg/src/main/j2me/org/spongycastle/openpgp/PGPSecretKey.java

@@ -278,7 +278,16 @@ public class PGPSecretKey
     {
         return pub.getUserIDs();
     }
-    
+
+    /**
+     * Return the S2K object used to encrypt this secret key.
+     *
+     * @return an iterator of Strings.
+     */
+    public S2K getS2K() {
+        return secret.getS2K();
+    }
+
     /**
      * Return any user attribute vectors associated with the key.
      * 

libraries/spongycastle/pg/src/main/java/org/spongycastle/openpgp/PGPSecretKey.java

@@ -431,7 +431,16 @@ public class PGPSecretKey
     {
         return pub.getUserIDs();
     }
-    
+
+    /**
+     * Return the S2K this secret key is encrypted with.
+     *
+     * @return the S2K for this key.
+     */
+    public S2K getS2K() {
+        return secret.getS2K();
+    }
+
     /**
      * Return any user attribute vectors associated with the key.
      *