Syzygy tablebases

Adds support for Syzygy tablebases to Stockfish.  See
the Readme for information on using the tablebases.

Tablebase support can be enabled/disabled at the Makefile
level as well, by setting syzygy=yes or syzygy=no.

Big/little endian are both supported.

No functional change (if Tablebases are not used).

Resolves #6

src/Makefile

@@ -75,6 +75,12 @@ bsfq = no
 popcnt = no
 sse = no
 pext = no
+syzygy = yes
+
+ifeq ($(syzygy),yes)
+	OBJS += syzygy/tbprobe.o
+	CXXFLAGS += -DSYZYGY
+endif
 
 ### 2.2 Architecture specific
 
@@ -398,7 +404,7 @@ install:
 	-strip $(BINDIR)/$(EXE)
 
 clean:
-	$(RM) $(EXE) $(EXE).exe *.o .depend *~ core bench.txt *.gcda
+	$(RM) $(EXE) $(EXE).exe *.o .depend *~ core bench.txt *.gcda ./syzygy/*.o
 
 default:
 	help