Cleaned up source, directories, and added header file to improve general readability

Makefile

@@ -1,13 +1,14 @@
-CC?=gcc
-CFLAGS+=
+CC	   ?= gcc
+CFLAGS += -Wall -Wextra
+LIBS	= -lcurses
 
-all: 2048 2048_no_curses
+all: 2048
 
-2048: 2048_curses.c
-	$(CC) $(CFLAGS) 2048_curses.c -lcurses -o 2048
+2048: src/2048.c
+	$(CC) $(CFLAGS) src/2048.c -o 2048 $(LIBS)
 
-2048_no_curses: 2048_no_curses.c
-	$(CC) $(CFLAGS) 2048_no_curses.c -o 2048_no_curses
+2048nc: src/2048_no_curses.c
+	$(CC) $(CFLAGS) src/2048_no_curses.c -o 2048nc
 
 clean:
-	rm -f 2048 2048_no_curses
+	rm -f 2048 2048nc