[MERGE] Make function for escaping invalid XML characters public.

[Ian Clatworthy]

Ian Clatworthy has voted approve.
Status is now: Approved


For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C20090331204115.9450F57B8F%40charis.vernstok.nl.vernstok.nl%3E
Project: Bazaar