fixed issue where insertBefore would fail for newly created element

dom/node.js
* insertBefore: added check to determine if the node to be inserted has a parentNode before bluntly trying to remove it

test/document.js
+ added tests for previous/next siblings
simplified previous- and nextSibling to take advantage of the index method

dom/node.js
* previous-/nextSibling removed the self-contained indexing loops and switched to the index method on Simple instances
NodeList instances are now 'live', started work on namespaces by implementing Node.namespaceURI

dom/node.js
* implemented the 'namespaceURI' getter, which will now return null until namespaces are fully implemented
* the 'childNodes' property now provides a 'live' NodeList instance which will always reflect the the actual childNodes (prior to this the NodeList was 'static' and would require reset which would not reflect in referenced variables
- removed all deletions of the childNodeList member
* removed TODO from 'textContent' getter as it passes the tests
* changed object notation to be more consistent

dom/nodelist.js
+ added internal 'getItems' to always obtain a fresh reference to the the current items
+ added module initialization and scoping
* in order to prevent a caching behavior

dom/test.js
- removed all deletions of the childNodeList member

test/document
+ added various tests to test the 'live' nature of NodeList instances