Makefile doesn't crete "obj" directory

[Nekto89]

Makefile doesn't create directory so there are errors if you don't do it yourself.

makefile:12: recipe for target 'obj/cards.o' failed
make: *** [obj/cards.o] Error 1
make: *** Waiting for unfinished jobs....
makefile:12: recipe for target 'obj/tyrant.o' failed
make: *** [obj/tyrant.o] Error 1
Assembler messages:
Fatal error: can't create obj/deck.o: No such file or directory
makefile:12: recipe for target 'obj/deck.o' failed
make: *** [obj/deck.o] Error 1
Assembler messages:
Fatal error: can't create obj/xml.o: No such file or directory
makefile:12: recipe for target 'obj/xml.o' failed
make: *** [obj/xml.o] Error 1
Assembler messages:
Fatal error: can't create obj/sim.o: No such file or directory
makefile:12: recipe for target 'obj/sim.o' failed
make: *** [obj/sim.o] Error 1
Assembler messages:
Fatal error: can't create obj/read.o: No such file or directory
makefile:12: recipe for target 'obj/read.o' failed
make: *** [obj/read.o] Error 1
Assembler messages:
Fatal error: can't create obj/tyrant_optimize.o: No such file or directory
makefile:12: recipe for target 'obj/tyrant_optimize.o' failed
make: *** [obj/tyrant_optimize.o] Error 1