Merging v2.11.4 from the master branch.
o CLEANUP: Dropped argument 'field' for toNnn(), because the default
  is now NULL which corresponds to returning a DevEvalProduct object.
  In turn, this object has the pathname as it's value, which was the
  previous default 'field' value.  Also, as.character() on this object
  returns the (relative) pathname.
o BUG FIX: Now getPathname(..., relative=FALSE) returns the
  absolute pathname.
Moved getPathname() bug fix to v2.11.4
o Added favicon() device, which is a wrapper for png() with bells
  and whistles.  It has its own device options.  Updated toFavicon()
  to use default argument field="htmlscript", which generates an
  HTML script that dynamically sets the favicon.