Added dom.loadXML method

dom.js
+ added loadXML method, which accepts an XML string and creates a
DOMDocument from it
* changed the mechanics of creating SAXParser instances

sax.js
+ added parse method, which accepts a source string to be parsed into a
DOMDocument
added 'make todo' (*nix), updated dependencies

Makefile
+ added todo option

package.json
* updated dependencies