Batch Convert improvements : Resume (or Pause); Background conversion; right-click items

[meteorquake]

I think the title says it all, unless I've currently missed the obvious -
* There's currently a Stop button on the Batch Convert but no Resume button once you've pressed it. An alternative is to have a Pause button but I think presenting a Resume button in place of the Stop button would be ideal, presumably if the "resume" item is removed it could adjust the resume to the subsequent one that's still present, so the Resume would still be meaningful.
* Maybe some kind of background priority button would be useful too, rather like 7zip has. However instead of that (or as well as) I think it could have a box in the conversion settings for number of milliseconds to pause between items and this would allow people to fine-tune the load.
* Also since we're there, some extra menu items when you right-click items in the input list, such as open in xnviewmp, open in explorer, maybe an easy custom list of title : action (%1 representing the filename)
Cheers, David