Added ".." and "..." infix operators. Num implements them to
return Range objects. Those in turn implement the iterator
protocol, so now numeric for loops are easy:
for (i in 1..10) { ... }
I also cleaned up the Wren benchmarks to use this.
In the process, I discovered the method_call benchmark really
just showed loop peformance, so I unrolled the loops in all of
the languages to stress method calls.
Bob Nystrom