Generate bindings for HTMLFormElement.
auto merge of #818 : sonwow/servo/bindings, r=jdm
Paint background-color in text box
auto merge of #823 : june0cho/servo/inline_bgcolor, r=metajack

In case that inline element has `background-color`, bgcolor doesn't work.
Fix the error and add a test case.
Implement IDL based HTMLSmallElement binding