Bug 1086936 part 1 - Add a UI switch to disable custom profile selection process in Aurora. r=bsmedberg,jaws f=matej,shorlander

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extra : rebase_source : ca599ad502e6975ae02ce9884cc207bf1ac62168
Bug 1086936 part 2 - Add a flag to nsIAppStartup::quit that restarts the browser without using the same profile and use it for the Aurora UI switch. r=bsmedberg