Alternate rendering of list items as block elements (instead of
inline/final).
Check the built DOM is still coherent with styles on stylesheet
change, and propose to reload the document if not. Also
invalidate cache on close in that case so a new DOM is built
at next opening.
ReaderStyleTweak: fix tweak css duplication; when globally
enabled, when disabling and re-enabling locally, the css would
be added twice to the final CSS.
Also adds !important to "sub_sup_smaller" tweak, and increase
its priority so it can override "font_size_all_inherit".
Adds CreDocument:getCacheFilePath() for futur features.
