Add some extensions of XML

Hi Robson,

I believe .svg is already linked up to the XML file type.  We'll add .atom and .rss for the next version.  I'm not seeing any real info on the .feed extension on the web though, so I'm not sure we'll add that one.

In case you aren't aware, you can add any file extensions you want via the Settings flyout.  So you can add all these extensions to XML, even in the current version.

Thank you!

.FEED is the extension of feed templates of the CMS ExpressionEngine. I never see any other use of that, I have to confess.

Thank you so much! Thank you!