BATON ROUGE — Before plowing a pickup truck into a crowd of New Year’s revelers in New Orleans, killing 14 people, the man who carried out the Islamic State group-inspired attack had researched how to access a balcony on the city’s famed Bourbon Street and looked up information about a similar recent attack at a Christmas market in Germany, the FBI said. Nearly two weeks after Shamsud-Din Jabbar’s rampage, the FBI continues to uncover new information detailing the extensive planning by the 42-year-old Army veteran who scouted out the area multiple times in the months leading up to the attack.