Revised active page functions

Uses the global active_page rather than the document URL
Revised initImprovedPageTitles()

Uses isOnCatalog() and isOnThread(), as well as fixed indentation.
Add missing favorites links to the catalog
Call initImprovedPageTitles() on ready
Add option to open links in the catalog in a new tab
Unanimate new GIFs when disabled

Also fixed a typo I made earlier
Merge pull request #4 from Zaphkiel/master

Small improvements, notably favorites in the catalog