I18n resources stored into an XWikiDocument

Hi, I've added another proposed feature + some work implementing it at following URL: http://www.xwiki.org/xwiki/bin/view/Dev/Improved+XWikiMessageTool+for+manag… The idea is to use a Document for storing i18n resources instead of static files, so that they can be edited online and in a collaborative manner, and have their keys synchronized when the master document is updated. The proposal is also to use the "GNU Portable Object" format (PO) instead of properties file format, as it is widely used for translating software messages. There is however an interface that allows for implementing the tool for any format. Stéphane