removing nodes shouldn't remove models, definitively chopping this out
adds tests for 2 way bindings on input elements
sets up callbacks for input nodes... passes tests on radio buttons and checkboxes
making sure value doesn't exist to pass better values for textareas
some corrections on test expectations
ensuring false values can be set onto nodes
sets empty string if "value" passed as undefined
updates todomvc example w/ form using two way binds
defining tighter logic for setting values on radio buttons
updating todomvc app to reflect 2 way data bindings, adding edit todo bit. closes #8, #10