Implement play/stop cap and shell music

test/imgui/examples/example_win32_directx12/build_win32.bat

@@ -0,0 +1,8 @@
+@REM Build for Visual Studio compiler. Run your copy of vcvars32.bat or vcvarsall.bat to setup command-line compiler.
+@set OUT_DIR=Debug
+@set OUT_EXE=example_win32_directx12
+@set INCLUDES=/I..\.. /I..\..\backends /I "%WindowsSdkDir%Include\um" /I "%WindowsSdkDir%Include\shared"
+@set SOURCES=main.cpp ..\..\backends\imgui_impl_dx12.cpp ..\..\backends\imgui_impl_win32.cpp ..\..\imgui*.cpp
+@set LIBS=d3d12.lib d3dcompiler.lib dxgi.lib
+mkdir Debug
+cl /nologo /Zi /MD /utf-8 %INCLUDES% /D UNICODE /D _UNICODE %SOURCES% /Fe%OUT_DIR%/%OUT_EXE%.exe /Fo%OUT_DIR%/ /link %LIBS%