Revert "(EMSCRIPTEN) add shared context support"

This reverts commit 96feb074d085977345fe11363a1844136303ab68.
(EMSCRIPTEN) add analog emulator support
(iOS) Some pbxproj fixes
(iOS) Build fix
(iOS) Fix up iOS solution AGAIN
(Apple) Nit
(Apple) Doing it through this godawful fucking IDE now so that Xcode
doesn't get the chance to crap all over changed paths again
(iOS) And another 'build fix' now - let's hope things work now
as expected
(Settings data) Add Overlay Enable option
(Settings data) Move setting around
(Settings data/iOS) Fix crash at startup with new config - audio latency was being set to
0 because g_defaults.out_latency would point to 0 - instead, we check
if g_defaults.settings.out_latency is higher than 0 and if so, set the
setting to that - otherwise, default to value in config.def.h

On an unrelated note - the setting I just added to settings_data.c still
doesn't show up. This code is in need of some serious refactoring
(Settings data) Some cleanups
(Apple/iOS) Cleanups of menu.m
(iOS) menu.m - more cleanups/build fixes
(Settings data) Create enum for settings list
(Setting data) Make settings data more readable
(Setting data) Add group name/subgroup name too to settings
(Settings data) Fix warning
(Apple OSX) settings.m - style nits
(Apple) Move location/camera code into separate files