[v25] Templating, theme improvemtns & other fixes

* Fixed iOS rotation / zooming with the help of TCB
* Fixed appends double-encoding HTML, with thanks to Stephen Taylor
* Fixed unable to delete corrupted posts unless signed in
NOTE: the class `nnf_error` was added to `<article class="nnf_post
nnf_op">` in "delete.html"
* Updated to DOMTemplate v16, much better handling of HTML / XML