Refactor remaining toggle functions
(Menu) Implement action_start callback as well
(menu_common_backend.c) Cut down on some code duplication
Reduce header includes in menu_common_backend.c
(Menu) Add missing extern C namespaces for C++ builds
Get rid of some unnecessary header includes in rgui.c
Merge pull request #1134 from lakkatv/xmb

(Menu) Ticker line
Merge pull request #1135 from lakkatv/xmb

(Menu) Fade on search
(lakka.c) Get rid of some unneeded header includes
(glui.c) Get rid of some unnneeded header includes
(XMB) Get rid of some unneeded header includes
(menu_common_backend.c) Get rid of some unnecessary header includes
Cleanups in menu_common_backend.c
(Menu) Reimplement deferred_core list without needing need_refresh
menu_shader_manager_setting_toggle - rename id to type
start reducing calls to menu_clear_navigation
Revert "start reducing calls to menu_clear_navigation"

This reverts commit 202b1e2006a3ca03ef5dbe161ac4a4692af77ab3.
Add bool pending_push parameter to menu_clear_navigation
(XMB) Fix navigation_clear regression