fix for very rare null pointer exception if picking the library retur…

…ns an intent with no null data

src/com/cgogolin/library/Library.java

@@ -856,7 +856,7 @@ protected void onActivityResult(int requestCode, int resultCode, Intent intent)
             case LIBRARY_FILE_PICK_REQUEST:
                 if(resultCode == Activity.RESULT_OK)
                 {
-                    if (intent != null) {
+                    if (intent != null && intent.getData() != null) {
                         if(setLibraryPathDialog!=null)
                         {
                             setLibraryPathDialog.dismiss();