Calendar view's day view: thicker separator at 00:00

When using the new option "Daily timeline starts at",
make the separator line between 23:00 and 00:00 thicker.
Also tweak time picker to pick minutes by units of 10,
and remove max hour (06:00) limitation.

frontend/ui/widget/datetimewidget.lua

@@ -211,7 +211,7 @@ function DateTimeWidget:createLayout()
             value = self.min,
             value_min = self.min_min or 0,
             value_max = self.min_max or 59,
-            value_step = 1,
+            value_step = self.min_step or 1,
             value_hold_step = self.min_hold_step or 10,
             width = number_picker_widgets_width,
         }

plugins/statistics.koplugin/calendarview.lua

@@ -911,11 +911,21 @@ function CalendarDayView:refreshTimeline()
         })
     end
     -- Horizontal lines
+    local idx_00h00
+    if self.reader_statistics.settings.calendar_day_start_hour and self.reader_statistics.settings.calendar_day_start_hour ~= 0 then
+        idx_00h00 = 24 - self.reader_statistics.settings.calendar_day_start_hour
+    end
     for i=0, 24 do
         local offset_y = self.timeline_offset + self.hour_height * i
+        local height = Size.border.default
+        if idx_00h00 and i == idx_00h00 then
+            -- Thicker separator between 23:00 and 00:00
+            offset_y = offset_y - math.floor(height/2) -- shift it a bit up
+            height = height * 2
+        end
         table.insert(self.timeline, FrameContainer:new{
             width = self.timeline_width,
-            height = Size.border.default,
+            height = height,
             background = Blitbuffer.COLOR_LIGHT_GRAY,
             bordersize = 0,
             padding = 0,

plugins/statistics.koplugin/main.lua

@@ -1088,7 +1088,9 @@ The max value ensures a page you stay on for a long time (because you fell aslee
                             local start_of_day_widget = DateTimeWidget:new{
                                 hour = self.settings.calendar_day_start_hour or 0,
                                 min = self.settings.calendar_day_start_minute or 0,
-                                hour_max = 6,
+                                min_max = 50,
+                                min_step = 10, -- we have vertical lines every 10mn, keep them meaningful
+                                min_hold_step = 30,
                                 ok_text = _("Set time"),
                                 title_text = _("Daily timeline starts at"),
                                 info_text =_([[