Bug 1033463 - don't null out gEditBookmarkOverlay, r=mak

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extra : rebase_source : ca28e8c7faba88eb4851737c960fe89a61e20955
Bug 577892 - allow icons to change when href attribute is set directly, with automated test, r=dolske,bz

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extra : rebase_source : 8b74cb3e4c60df4b84c207f2ae1bc371e238d19d