Misc. Shader refactors

Copy SDL2.dll when compiling citra-qt with msvc

gdbstub: const correctness changes

game_list: Add a context menu with "Open Save Location"  option

Kernel: remove object's waiting thread if it is dead

Also uses size_t as the length indicator type, as is common with buffers.

Threading: Reworked the way our scheduler works.

Common: Fix gcc build on macOS

Fix debug build from #2249

gdbstub: Remove global variable from public interface

Service/CECD: Add cecd:ndm service

hid: Get rid of a double -> float truncation warning

Currently, this is only ever queried, so adding a function to check if the
server is enabled is more sensible.

If directly modifying this externally is ever desirable, it should be done
by adding a function to the interface, rather than exposing implementation
details directly.

core: Add missing #pragma once directives where applicable

float literals need to have the 'f' prefix.

act: Fix docstring typo

These aren't the AM services.

shader_jit_x64: Use LOOPCOUNT_REG as a 64-bit reg when indexing

Service/ACT: move ACT services to folder

* Add a context menu with a "Open Save Data Location" action

Memory: Always flush whole pages from surface cache

This prevents individual writes touching a cached page, but which don't
overlap the surface, from constantly hitting the surface cache lookup.

VideoCore: Eliminate an unnecessary copy in the drawcall loop

Convert shader JIT to Xbyak