add bookmarks bulk actions (auto or supervised)

[TarekJor]

add auto or semi-auto bulk actions to merge, join, diff bookmarks from duplicates considering "folder" and "tags" (#42 #47) fields

For example from bookmark duplicates checker (duplicate criteria: by.url)

ocurrence1: title, url, tag1, folder1
ocurrence2: title, url, tag2, folder2
... etc

possible conflicts

title and url => must be unique (no conflict)
(ignore this 1* ) tag1 & tag2 => resolve ocurrence merged: title, url, tag1, tag2
(1*edit: Firefox considers url.tagged as unique yet, ignore this)
folder1 & folder2 => override (one or another) or convert "folder to tags" (via an folder.2.tags function)

[tDeContes]

Since tag merging has no sense (if I understand),
is there still something more than in #38?

[tsilvs]

Actually, merging tags from multiple bookmarks with the same URL can be pretty convenient.