fix escaping in diff view
fix escaping in diff view

Avoid that HTML entities appear in the table header, by going through
a data attribute, and replace script with hidden textareas to avoid
using "safe".

famz/patchew,famz/patchew,famz/patchew,patchew-project/patchew,famz/patchew,patchew-project/patchew,patchew-project/patchew,patchew-project/patchew