Replace radical.widgets.checkbox with wibox.widget.checkbox

Radical checkbox widget is no longer needed, it still here,
but no longer used, maybe @Elv13 have some plans with it.

README.md

@@ -353,7 +353,6 @@ Radical also use the some of the same theme options as awful.menu, plus some:
 | menu_corner_radius           | Arrow based menu corner radius         | Number (default = 10)     |
 | dock_corner_radius           | The dock menu type corner radius       | Number (default 10)       |
 | menu_outline_color           | Arrow menu outer border color          | String/Gradient/Pattern   |
-| menu_checkbox_style          | The style used for checkboxes          | "holo" or "default"       |
 
 
 Styling can also be done using the icon_transformation option. This feature

item/common.lua

@@ -1,6 +1,5 @@
 local wibox     = require( "wibox"     )
 local beautiful = require( "beautiful" )
-
 local module = {}
 
 -- Apply icon transformation
@@ -59,24 +58,15 @@ end
 -- Setup the checkbox
 function module.setup_checked(item, data)
     if item.checkable then
-        item.get_checked = function()
-            if type(item._private_data.checked) == "function" then
-                return item._private_data.checked(data,item)
-            else
-                return item._private_data.checked
-            end
-        end
+        local ck = wibox.widget.checkbox(item.checked or false)
 
-        local ck = wibox.widget.checkbox(item.checked or false, {
-            style = beautiful.menu_checkbox_style,
-            color = beautiful.fg_normal
-        })
-
-        item.set_checked = function (_,value)
-        item._private_data.checked = value
+        item.set_checked = function(_,value)
             ck.checked = value
-        item._internal.has_changed = true
         end
+        item.get_checked = function()
+            return ck.checked
+        end
+
         return ck
     end
 end

radial.lua

@@ -7,7 +7,6 @@ local base      = require( "radical.base"             )
 local awful     = require( "awful"                    )
 local util      = require( "awful.util"               )
 local button    = require( "awful.button"             )
-local checkbox  = require( "radical.widgets.checkbox" )
 local beautiful = require( "beautiful"                )
 local naughty   = require( "naughty"                  )
 local wibox     = require( "wibox"                    )

widgets/init.lua

@@ -2,11 +2,9 @@
 local wibox = require("wibox")
 
 wibox.layout.grid     = require( "radical.widgets.grid"     )
-wibox.widget.checkbox = require( "radical.widgets.checkbox" )
 wibox.widget.slider   = require( "radical.widgets.slider"   )
 
 return {
-    checkbox        = require( "radical.widgets.checkbox"        ),
     scroll          = require( "radical.widgets.scroll"          ),
     filter          = require( "radical.widgets.filter"          ),
     fkey            = require( "radical.widgets.fkey"            ),