Change default extension for XLIFF files

[willydee <willydee@…>]

According to http://www.oasis-open.org/committees/xliff/documents/xliff-specification.htm, an XLIFF file should have the extension ".xlf". Please update the framework to use this as default extension for language files, as some XLIFF translation tools don't accept .xml files.

Please keep the support for .xml files for not breaking existing applications.

[wei]

Sorry, the design is not flexible enough to be fixed easily :(

[willydee]

I have a suggestion after inspecting the code of MessageSource? and it's derivatives. What about renaming the current MessageSource?_XLIFF to MessageSource?_XML and extend MessageSource?_XLIFF from it by just overriding

	protected $dataExt = '.xlf';

This would indeed break BC, but there's just one attribute to modify in application.xml to fix the problem, no aggravating application changes are required.

[wei]

Supports .xlf if .xml is missing