Acidfree breaks statistics module

The function acidfree_pager_creator() does not restore the value of $_GET['q'] after it is done working with it. This results in incorrect data being logged by the statistics module. (When viewing a picture, the log shows that the parent was viewed instead, according to the link in the file)

I have attached a patch which restores the value after the pager is created and fixes this problem.

-- Doug