Merge pull request #900 from lakkatv/lakka

(Lakka) Display about 9 horizontal icons instead of 6
(Menu) Refactor away MENU_CONTENT_HISTORY_PATHckend.c.swp
(Menu) Split up ACTION_OK logic into separate function
(Menu) Rename menu_common_iterate_action to menu_action_ok
(Menu) Move some descriptions to settings_data.c
Move DEFAULT_SHADER_TYPE from driver.h to gfx/shader_common.h
Remove unused menu_ctx_find_driver
Move all drivers to beginning of driver.c
Combine all driver_index* functions
find_driver_index - cleanups
Refactor find_driver_index
Refactor find_driver_index
Cleanups - remove extraneous else
Refactor find_prev_* / find_next_* functions
Get rid of some duplicate get_prev/get_next functions
Refactor find_prev/find_next menu driver functions
(driver.c) Cleanups
Remove unused keybind_set_id
Move MAX_ARGS define to frontend.c
(miscellaneous.h) Get rid of some extranous else