Changing in item loading priority midflight

[Arthur Debert]

Hi Folks.

This is a pretty frequent feature request: changing an item's priority
after the item has been added.
After revision 83, you can change an items priority with"
<BulkLoader instance>.changeItemPriority(itemKey : String,
newPriority : int)

where:
key -> polimophic parameter - the same for many functions of
BulkLoader - can be the item's id as a string, the item url as a
UrlRequest or a url as a String
newPriority -> an int indicating the new priority for the item
identified by key

returns a Boolean:
true if the item has been found, false otherwise.

Please note that this will not kill connections already open. The next
connection to be open will take the new priority in consideration.

Cheers
Arthur