Block qt signals when manually setting value to avoid emitting an event in wxQT, thanks @seandpagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77927 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Improve slider implementation in wxQT, thanks @seandpagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77928 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Improve wx->qt filter mapping logic in wxQT, thanks @seandpagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77929 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Add inverted flag support to slider in wxQT, thanks @seandpagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77930 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775