Move test JS into HTML files

Fixes #896.
Fix some missing end-of-file newlines
use spawn_with in lieu of cells
auto merge of #958 : tikue/servo/master, r=pcwalton

Cells are generally less readable, and spawn_with makes many of them unnecessary.
auto merge of #957 : kmcallister/servo/inline-js, r=jdm
Rename the element field of the DOM Node hierarchy

Renamed htmlelement, and element

Fixes #924
Rename the node field of the DOM node hierarchy

Renamed the Node elements

Fixes #924
auto merge of #959 : luisbg/servo/master, r=jdm

Issue #924