Explanation of the reasons for mapping imported UUIDs into new local

UUIDs.

src/com/fsck/k9/preferences/StorageImporterEncryptedXml.java

@@ -23,6 +23,15 @@ public class StorageImporterEncryptedXml implements IStorageImporter {
             String data = dataset.data.toString();
             List<Integer> accountNumbers = Account.getExistingAccountNumbers(preferences);
             Log.i(K9.LOG_TAG, "Existing accountNumbers = " + accountNumbers);
+            /**
+             *  We translate UUIDs in the import file into new UUIDs in the local instance for the following reasons:
+             *  1) Accidentally importing the same file twice cannot damage settings in an existing account.
+             *     (Say, an account that was imported two months ago and has since had significant settings changes.)
+             *  2) All UUIDs used in the local instance will be generated with the same generator.
+             *  3) Importing a single file multiple times allows for creating multiple accounts from the same template.
+             *  4) Exporting an account and importing back into the same instance is a poor-man's account copy (until a real
+             *     copy function is created, if ever)
+             */
             Map<String, String> uuidMapping = new HashMap<String, String>();
             String accountUuids = preferences.getPreferences().getString("accountUuids", null);