Bug 966698 - Tabs toolbar shouldn't have a top margin in fullscreen mode. r=Gijs

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extra : rebase_source : f40fdd8ef1bf2c1fea9ba0dfa7d60136e700297c
Bug 973189 - Get rid of the browser.ctrlTab.recentlyUsedLimit pref. r=ttaubert

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extra : rebase_source : 353e5533fa5c88624a0c3e94170c131485841609