xml combiner: edit comment
xml combiner: rename variables, i was getting confused.
xmlcombiner: use xpath to get the articles
xmlcombiner: combine arrays and sort with usort according to date
xmlcombiner: create new doc and append articles in order
xmlcombiner: refactor event callback with same code from article callback
xmlcombiner: add usort callback for events
Merge branch 'master' of github.com:/ITS-UofIowa/housing.uiowa.edu