gl_shader_disk_cache: Skip stored shader variants instead of asserting

Port citra-emu/citra#4749: "web_service: Misc fixes"

yuzu/hotkeys: Remove unnecessary constructor

yuzu/compatdb: Remove unnecessary qualifiers

configure_dialog: Remove the Whats This? button from the dialog

core/memory: Remove unused FlushMode enum

Corrections and Implementation on GPU Engines

externals: Update dynarmic to master

The behavior of the Hotkey constructor is already accomplished via in-class member
initializers, so the constructor is superfluous here.

Keeps the code consistent in regards to how the buttons are referred to.

Recent changes to memory-related code resulted in this being unused, so
we can remove it.

Better instruction support has been added since the last update.

travis: Update to using Xcode 10.2

Keeps the CI toolchain updated. This is also necessary for updating
dynarmic.

core/frontend/emu_window: Make GraphicsContext's destructor virtual

common/zstd_compression: Remove #pragma once directive from source file

gl_rasterizer: Silence unused variable warnings

The backend is not used until we decide to submit the testcase/telemetry, and creating it early prevents users from updating the credentials properly while the games are running.

This isn't used anywhere, so we can get rid of it.

Makes use of src, so it's not considered unused.

Introduced in 72477731. This is only
necessary within header files.

This class is used in a polymorphic context, so destruction of the
context will lead to undefined behavior if the destructor isn't virtual.

Port citra-emu/citra#4215: "travis: Use Ninja for Travis builds"

Instead of asserting on already stored shader variants, silently skip them.
This shouldn't be happening but when a shader is invalidated and it is
not stored in the shader cache, this assert would hit and save that
shader anyways when the asserts are disabled.

Unintentionally introduced in 552d5071

Port citra-emu/citra#3839: "travis: use prebuilt image"

gl_shader_disk_cache: Improve precompiled shader cache generation speed and size

shader_ir: Miscellaneous fixes

kernel/vm_manager: Remove usages of global system accessors

video_core: Silent -Wswitch warnings

Corrections on Half Float operations: HADD2 HMUL2 and HFMA2

kernel/svc: Clean up wait synchronization related functionality

Allow picking a Compatibility Profile for OpenGL.

Port citra-emu/citra#4748: "Launch directly in Mac without terminal"

applets: Add AppletManager and implement PhotoViewer and Error applets