Fix issue #59.

Dates were only shown on the x-axis for yearly data.

src/@dseries/plot.m

@@ -56,22 +56,8 @@ switch ndseries
     end
     axis tight;
     id = get(gca, 'XTick');
-    if isequal(id(1),0)
-        dates = strings([o.dates(1)-1,o.dates(id(2:end))]);
-        skip_relabeling=0;
-    else
-        ID = id(find(isint(id)));
-        if any(ID<o.dates(1).double) || any(ID>o.dates(end).double)
-            skip_relabeling=1; %hold on was used so that axis tight did not restrict current xlim to dseries used.
-        else
-            set(gca,'XTick',ID);
-            dates = strings(o.dates(ID));
-            skip_relabeling=0;
-        end
-    end
-    if ~skip_relabeling
-        set(gca,'XTickLabel',dates);
-    end
+    Dates = strings(o.dates(id));
+    set(gca,'XTickLabel', Dates);
   case 2
     [o0, o1] = align(o, varargin{1});
     if isequal(nvariables,1)