Allow reading lfm documentation in lfm while making the document available in
${LOCALBASE}/share/doc/lfm

Index: lfm/actions.py
--- lfm/actions.py.orig
+++ lfm/actions.py
@@ -1111,11 +1111,13 @@ def help_menu():
         else:
             docfile = {'r': 'README', 'n': 'NEWS', 't': 'TODO', 'l': 'COPYING'}.get(ret[0])
             try:
-                filename = pkg_resources.resource_filename('lfm', 'doc/' + docfile)
-                utils.run_on_current_file(app.cfg.programs['pager'], filename)
-            except NotImplementedError:
-                buf = str(pkg_resources.resource_string('lfm', 'doc/' + docfile), 'UTF-8')
-                InternalView(docfile, [(l, 'view_white_on_black') for l in buf.splitlines()], center=False).run()
+                filename = '${LOCALBASE}/share/doc/lfm/' + docfile
+                with open(filename) as f:
+                    buf = f.readlines()
+                f.close()
+                InternalView(docfile, [(l, 'view_white_on_black') for l in buf], center=False).run()
+            except Exception as e:
+                DialogError('Cannot read the doc!\n{}'.format(str(e)))
         return refresh()
     else:
         return RetCode.nothing, None