On Valentine’s Day Mr. Market clearly can’t commit. Dow Industrials (^DJI) have now alternated between gains and losses for six straight sessions. Still romance is far from dead. Amazon (AMZN) advanced a further 4.16% after announcing an expanded broadcasting agreement with “Tiffany network” CBS Corp. (CBS) to show content including Everybody Loves Raymond.    Comcast (CMCSA) based in the City of Brotherly Love added on 2.98% to finish at its highest level since 1999. And aging Lotharios everywhere now have no excuse not to go down on one knee after an upgraded Zimmer Holdings (ZMH) hit a fresh 52-week peak on high hopes for its Persona Knee replacement. ...