Merge pull request #859 from tobiasjakobi/fixes

exynos: first batch of fixes/improvements for font rendering
(Menu) Refactor setting_toggle callbacks
Refactor menu_common_settings_set
(Menu) Refactor setting_set
(Menu) Refactor more settings functions - pass rarch_settings_t *
pointer variable
refactor setting_data_find_setting - can now return NULL if it couldn't
find the setting according to key
(Lakka) Remove libpng dependancy and use lowercase variables
Merge pull request #861 from lakkatv/lakka

(Lakka) Remove libpng dependancy and use lowercase variables
file_list.c/h - move struct to file_list.h
file_list.c - cleanup
(Menu) Refactor settings
(Menu) Refactor settings pt. 2
(Menu) Group MENU_SETTINGS_NETPLAY_DELAY_FRAMES
(Menu) Refactor settings pt. 3
lakka: Fix overflow possibilities when copying to icon_dir

strcpy also copies over the null-terminator as well.
(PS3) Build fixes
Merge pull request #862 from lioncash/lakka

lakka: Fix overflow possibilities when copying to icon_dir
(Settings data) Add ST_DIR type
(Menu) Add step variable for rarch_setting_t
Add 'enforce minrange/maxrange' to settings_data