Fix date display in Principal XML output.  Might as well support getctag too.
Fix date display in Principal XML output.  Might as well support getctag too.

lkraav/davical-rss-feature-branch,lkraav/davical-rss-feature-branch,lkraav/davical-rss-feature-branch,lkraav/davical-rss-feature-branch