Bug 876033 - Add arranged event to richgrid, event cleanup. r=mbrubeck

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extra : rebase_source : bb5b699fcdfd2024030c051f13fb13a28afd76c6
Bug 876033 - Reselect TopSites tiles when we undo deletion. r=mbrubeck

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extra : rebase_source : 38e8f9557d98b6bbdd2960f2a54550a388f19582
Bug 876033 - Add arrranged event test for richgrid, refactor TopSites tests, add test restore functionality. r=rsilveira

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extra : rebase_source : c256879c2e62f6f14c8914266d263373c0f10b6c