Adds a DimDom collection object to encapsulate multiple DimDom items without a parent item
// create a new collection
var collection = new DimDom.Collection([
new DimDom("p", "Some paragraph text"),
"Some standalone text",
document.createElement("div")
]);
// append collection to a document
collection.appendTo(someNode);
// use a collection as the children for a new DimDom instance
var parent = new DimDom("section", collection);
Adds a DimDom collection object to encapsulate multiple DimDom items without a parent item
resolves #7