better microbenchmark for pypy

pypy_micro.py

def fib(n):
   if n <= 1:
      return n
   else:
      return fib(n-1) + fib(n-2)

def main():
    for i in xrange(36):
        print "n=%d => %d" % (i, fib(i))

if __name__ == "__main__":
    main()