Facebook Inc (FB.O) said on Monday it would submit itself to an audit of how it controls hate speech in a bid to appease a growing advertising boycott of the platform, as it prepared to address a group of advertisers on Tuesday. The move comes as major advertisers such as Unilever (ULVR.L) and Starbucks (SBUX.O) have signed on to the "Stop Hate for Profit" campaign started by