Add new example with implementation of Perlin Noise

~4.2x speedup versus serial on OSX / gcc.
~2.9x speedup versus serial on Windows / MSVC.

examples/noise/Makefile

@@ -0,0 +1,26 @@
+
+CXX=g++ -m64
+CXXFLAGS=-Iobjs/ -O3 -Wall
+ISPC=ispc
+ISPCFLAGS=-O2 --target=sse4 --arch=x86-64
+
+default: noise
+
+.PHONY: dirs clean
+
+dirs:
+	/bin/mkdir -p objs/
+
+clean:
+	/bin/rm -rf objs *~ noise
+
+noise: dirs objs/noise.o objs/noise_serial.o objs/noise_ispc.o
+	$(CXX) $(CXXFLAGS) -o $@ objs/noise.o objs/noise_ispc.o objs/noise_serial.o -lm
+
+objs/%.o: %.cpp
+	$(CXX) $< $(CXXFLAGS) -c -o $@
+
+objs/noise.o: objs/noise_ispc.h 
+
+objs/%_ispc.h objs/%_ispc.o: %.ispc
+	$(ISPC) $(ISPCFLAGS) $< -o objs/$*_ispc.o -h objs/$*_ispc.h