auto-click encrypt/decrypt button when using an *_AND_RETURN Intent with EXTRA_DATA or ContentURI

Fixes issue 67

src/org/thialfihar/android/apg/DecryptActivity.java

@@ -328,7 +328,7 @@ public class DecryptActivity extends BaseActivity {
         updateSource();
 
         if (mSource.getCurrentView().getId() == R.id.sourceMessage &&
-            (mMessage.getText().length() > 0 || mData != null)) {
+            (mMessage.getText().length() > 0 || mData != null || mContentUri != null)) {
              mDecryptButton.performClick();
         }
     }

src/org/thialfihar/android/apg/EncryptActivity.java

@@ -394,7 +394,7 @@ public class EncryptActivity extends BaseActivity {
         updateButtons();
 
         if (mReturnResult &&
-            (mMessage.getText().length() > 0 || mData != null) &&
+            (mMessage.getText().length() > 0 || mData != null || mContentUri != null) &&
             ((mEncryptionKeyIds != null &&
               mEncryptionKeyIds.length > 0) ||
              getSecretKeyId() != 0)) {