Attached patch suppresses byte compiler warnings.

Most changes are to replace (require 'cl) with (require 'cl-lib). Few other
changes were also made simply by following messages printed by the byte
compiler, e.g., replacing show-branches with outline-show-branches,
org-pop-to-buffer-same-window with pop-to-buffer-same-window, and declaring
new-of as a dynamic variable to prevent it from being a free variable.