Kindle4NT improvements (#3745)

* [device][kindle4] add fake event to kindle4

* modify focusmanager to allow for more complex layout

The focusmanager now naviguate the layout by avoiding nil value
instead of relying on table lenght. It should be completely backward
compatible

* add Dpad naviguation to the touchmenu

* fix crash because virtualkeyboard on non touch device

the kindle4NT has no keyboard nor touch, the fix open the virtual
keyboard so koreader dont crash but it's not useable

* Enable device with keys to use the touchmenu

* Don't get stuck in reader progress statistics plugin

* [underlinecontainer] Fix and remove unused function

References #1898.

frontend/apps/reader/modules/readermenu.lua

@@ -53,7 +53,6 @@ function ReaderMenu:init()
     self.registered_widgets = {}
 
     if Device:hasKeys() then
-        self.key_events = { Close = { { "Back" }, doc = "close menu" }, }
         if Device:isTouchDevice() then
             self.key_events.TapShowMenu = { { "Menu" }, doc = "show menu", }
         else
@@ -241,7 +240,7 @@ function ReaderMenu:onShowReaderMenu(tab_index)
     }
 
     local main_menu
-    if Device:isTouchDevice() then
+    if Device:isTouchDevice() or Device:hasDPad() then
         local TouchMenu = require("ui/widget/touchmenu")
         main_menu = TouchMenu:new{
             width = Screen:getWidth(),
@@ -294,8 +293,10 @@ function ReaderMenu:_getTabIndexFromLocation(ges)
     if self.tab_item_table == nil then
         self:setUpdateItemTable()
     end
+    if not ges then
+        return self.last_tab_index
     -- if the start position is far right
-    if ges.pos.x > 2 * Screen:getWidth() / 3 then
+    elseif ges.pos.x > 2 * Screen:getWidth() / 3 then
         return #self.tab_item_table
     -- if the start position is far left
     elseif ges.pos.x < Screen:getWidth() / 3 then