start splitting game logic into Game class

Makefile

@@ -3,7 +3,7 @@ DC := gdc
 TARGET := game
 SOURCES := $(shell find src -iname '*.d')
 OBJECTS := $(patsubst %.d,%.o,$(SOURCES))
-DFLAGS := -I/usr/local/include/d
+DFLAGS := -I/usr/local/include/d -Isrc
 LDFLAGS := -lDerelictSDL -lDerelictGL -lDerelictGLU -lDerelictUtil -ldl -lGL -lGLU
 
 all: $(TARGET)