Add dedicated server build

src/Makefile.d/dedicated.mk

src/Makefile.d/platform.mk

src/d_main.c

src/dedicated/Sourcefile

src/dedicated/i_main.c

src/dedicated/i_net.c

src/dedicated/i_sound.c

src/dedicated/i_system.c

src/dedicated/i_threads.c

src/dedicated/i_video.c

src/hardware/hw_main.c

src/netcode/d_netcmd.c