Prep for "Read an XML File" Demo

Added a few handy methods to these objects to make them easier to read
in later.
Read an XML File

A quick example of how to read in an XML file (that, perhaps, you
created elsewhere) based closely on [this
example](http://www.javacodegeeks.com/2013/05/parsing-xml-using-dom-sax-
and-stax-parser-in-java.html).