Merge pull request #1249 from lakkatv/xmb

(XMB) Fix switch fall-through
Add prototype to settings_data.h
Merge pull request #1250 from lakkatv/xmb

(XMB) Display core title
Remove redundant conditions
xaudio: Fix a typo in xa_stop

Pretty sure we should set the pause var to true on stopping.
Add/fix some trivial null checks
Merge pull request #1253 from lioncash/null

Add/fix some trivial null checks
Merge pull request #1252 from lioncash/xaudio

xaudio: Fix a typo in xa_stop
Merge pull request #1251 from lioncash/cond

Remove redundant conditions
Add missing cast to node assignment
Fixup comment
Reimplement menu actions toggle/OK/start - get rid of fall-through
Cleanup code in menu_common_backend.c
(menu/menu_entries_cbs.c) Cleanup unused variables
Add audio_max_timing_skew setting

Let users enable very large timing skews if they don't mind
inaccurate audio pitch.
Merge pull request #1255 from mprobinson/timing-skew

Add audio_max_timing_skew setting
(Menu) Reimplement left/right scrolling
(Menu) Small cleanup of unused variable
(Menu) Make left/right work too for history list playlist entries
(OSX) Refactor apple_gfx_ctx_swap_buffers for OSX