Banner & Witcoff Ltd. added Manav Das as of counsel and John J. Whelan and Brent K. Whitlock as associates to its intellectual property practice.All three focus their practices on intellectual property matters, including post-grant proceedings, appellate matters, licensing, preparation and patent prosecution, as well as client counseling.• Perkins Coie LLP added Kevin L. Kolton as a partner in the construction practice.  Kolton represents energy companies, commercial project owners and other industry …