* use fopen in DataManager::ReadScriptFromFile

* rename myfopen to mywfopen

* use std namespace

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Co-authored-by: salix5 <salix5566@gmail.com>

* update the header file of CGUIImageButton

* CGUIImageButton inherit from IGUIButton

* copy implementation from irrlicht 1.8.5

* remove ClickTime, HoverTime, FocusTime

only used in CGUIButton::draw

* remove CGUIButton.h

fix rebase problems

fix

This reverts commit 92db0f7311df58fa1e5b42e106bb7c497d8ca4ea.

This reverts commit fd4c3855.