Re-write in TypeScript

Re-write to use xmlcreate (greatly simplifies module source)

Added support for the ECMAScript 2015 Map and Set objects

New method of calling module:

var js2xmlparser = require("js2xmlparser");

var root = "root";
var data = {hello: "world"};
var options = {};

// old method (no longer works):
// js2xmlparser(root, data, options);

// new method:
js2xmlparser.parse(root, data, options);

New options and changes to functionality of some existing options:

• declaration contains additional options
• attributeString has additional functionality
• valueString has additional functionality
• The functionality provided by prettyPrinting is now provided by the new format option, which contains additional options
• arrayMap is now wrapHandlers to reflect the fact that wrapping is provided for both arrays and ES2015 sets
• convertMap is now typeHandlers to match the name change to arrayMap
• The functionality provided by useCDATA is now provided by the new cdataInvalidChars and cdataKeys options, which also provide additional functionality
• Added support for document type definitions using the dtd option