Compile with Optimization Flags

[zsxing99]

Type/Flag	No OP Flag	-O3	-O2
CV BAU1	22s	21s	21s
immediate CV BAU2	~3s	~3s	~3s
Basin BAU 1	~11s	~10s	~10s
immediate Basin BAU 1	~1.7s	~1.6s	~1.6s

I was noticing a slight speedup with -O3 or -O2, using 6 threads. I guess it is already optimized, but there is no harm to add -O2 flag.

I will leave the decision to Giorgos if you want the -O3 or -O2 flag.

gcc optimization options