Implements auto paging feature for SG and hides all joined giveaways. Also attempts to replicate Easy SteamGifts Join button if ESG installed.
Draft version of the script.
Working features:
* hides joined giveaways;
* supports auto-paging;
* adds ESG join button (via a dirty hack);
* hide similar giveaways feature should work (yet another hack).
Not supported features:
* ESG win chance is not calculated for paged giveaways (seems like I have to calculate it myself :/ ).
