Enable conversion of (some) standard TEI P5

Providing an option --xmlid-to-textsigle
to convert P5 xml:id attributes to three part I5-sigles

Resolves #4
Resolves #5

Change-Id: I8fd23b7021c25cf4d80234a0570d06dea78e7813
diff --git a/Changes b/Changes
index 79d0bbc..5c4f541 100644
--- a/Changes
+++ b/Changes
@@ -1,3 +1,9 @@
+        - Conversion of standard TEI P5 should now work, at least
+          in some cases.
+        - Option --xmlid-to-textsigle <from-regex>@<to-c/to-d/to-t>
+          added to convert standard P5 text id attributes to I5
+          sigles with three parts.
+
 2.3.4 2022-11-09
         - Improve stability of XML entity replacement.
         - Check version for script and KorAP-Tokenizer