[sandbox] working on json support
Merge branch 'dev' of github.com:xboot/xboot into dev

Conflicts:
	src/arch/x64/mach-sandbox/libsandbox/sandbox-sdl-event.c
	src/arch/x64/mach-sandbox/libsandbox/sandbox.c
	src/arch/x64/mach-sandbox/libsandbox/sandbox.h