pkgload 1.5.3

• When reloading a package, load_all() now runs the unload hooks of the
  previously loaded package (.onUnload() and user hooks registered with
  setHook()), whether it was loaded with pkgload or regularly. The old
  namespace and its DLL are still kept loaded so that dangling references
  continue to work, and errors thrown from .onUnload() are demoted to
  warnings so that they can't prevent reloading (#253).