[css] fix regression introduced by 6548:fd36c1049eed: we actually need display:block on box <a> to get proper behaviour on mouse hover

[js/ajax] use proper operator

[javascript] fix loadRemote implementation for synchronous requests In case of synhronous requests, loadRemote is supposed to return the "interpreted" server result (e.g a json object, a DOM object, ...). $.ajax() always return the XHR object, so we have to use the success callback to capture the actual server result and return it later.

[js preferences] fix various pb with js for preferences form: buggy clearPreviousError, bad prototype of callbacks given to validate form, dunno how error display was expecting to work...

add note

[js/ajax] fix deferred race condition

breadcrumbs/edid_box are now contextual component (closes #1334196)

[boxes] use a new separator instead of clumsy htmlwidget's one which close and reopen the <ul> (loosing any list class on the way)

js cleanup

[css] cleanup and fix by removing display: block on <a> in boxes also, add class a.action to ease action links like [+] in boxes like bookmark box without having to refine css per box id.