[Suggestion] Filter items when creating an item set based on selected champion/map

Since there is no dedicated suggestion board, I thought this the best place to put this. I believe that the items in the item set creator should be filtered by champion/map if the item set is restricted that way. This will keep the lists clean and make creating sets easier.

This came to mind when I ran into Wooglet's Witchcap and Entropy which are both not available on Summoner's Rift, but whose tool tips don't tell you that. If I specify that this item set should be restricted to only Summoner's Rift, the items list should only show me items available on that map. This would keep me from running into this problem.

This could then be extended to champion specific items. If I am making an item set for Kayle , I have no reason to see items only for Viktor .