This had been forgotten in df81fa11.

Fixes #1711.

citra: Remove GLFW, Add SDL2

FindSDL2: Do not CACHE SDL2_* variables if library is not found

EmuWindow_SDL2: Set minimal client area at initialisation time

EmuWindow_SDL2: Corrections

EmuWindow_SDL2: Fix no decorations on startup on OS X

cmake: windows_copy_files

This commit:
* Adds a new subproject, audio_core.
* Defines structures that exist in DSP shared memory.
* Hooks up various other parts of the emulator into audio core.

This sets the foundation for a later HLE DSP implementation.

Previously the Mac app didn't have any icon.

Instead of letting CMake re-generate an automatic Info.plist file on
every build, use our own. This allows greater control on the application
bundle settings.

This is exposed in the GUI as a new "CiTrace Recording" widget.

Playback is implemented by a standalone 3DS homebrew application (which only runs reliably within Citra currently; on an actual 3DS it will often crash still).

This will help packaging tremendously, as a `make DESTDIR=… install` will now
put every file at their place (on Linux and related).

Updated the copy commands to run on post_build and use generator expressions to simplify the code as well

Changes to bring the previous commits in line with the comments on thepull request. Made the debug build a true debug build with no optimizxations and the RelWithDebInfo is what it says it is too. Changed the copying of the dlls to the build directories to happen at configuration time instead of build time

More changes to the CMakeFiles for better MSVC compatibility. Added in the RelWithDebInfo target and setup copying the Qt 5 Dlls to the output directories.

Passing -pthread to GCC as a flag makes it both link to libpthread, and make C standard library routines reentrant. This makes the additional explicit links unnecessary.

Additionally, on OSX, this is the default behavior, and clang will print a message about it being unused if it's present there.

This both reduces redundancy in add_executable definitions, and makes it easier to link additional libraries. In particular, extra libraries are needed on OSX - see next commit.

Stubbed CreateMemoryBlock

Using Berkeley sockets, and Winsock2.2 on Windows.
So far ftpony creates the socket and accepts incoming connections

SOC_U: Renamed functions to maintain consistency

Also prevents possible scope errors / conflicts with the actual Berkeley socket functions

SOCU: Close all the opened sockets when cleaning up SOCU

The X11 libraries don't need to be specified when doing dynamic linking

This class has a few advantages over the regular QSpinBox:
- QSpinBox stores its as signed 32 bit integers, which for instance is unsuitable for representing memory addresses. CSpinBox uses 64 bit integers instead.
- QSpinBox does not provide an easy way to handle number input from bases different than 10.
- QSpinBox is quite inflexible in general and almost any sort of customization requires reimplementing it anyway.

Uses QSettings on citra-qt, and inih on citra-cli.

Several cleanups to the buildsystem:
 - Do better factoring of common libs between platforms.
 - Add support to building on Windows.
 - Remove Qt4 support.
 - Re-sort file lists and add missing headers.

This should fix the GL loading errors that occur in some drivers due to
the use of deprecated functions by GLEW. Side benefits are more accurate
auto-completion (deprecated function and symbols don't exist) and faster
pointer loading (less entrypoints to load). In addition it removes an
external library depency, simplifying the build system a bit and
eliminating one set of binary libraries for Windows.

Changes for clarity of comments, removed redundant compiler flags.