+* this file should go away before asking for a review :)
* I think we should wait for indexing-by-arrays-2, since this would clean up
duplication, since the indexing is getting slowly fairly complex.
* iterating over a transposed array still fails.
+* next_skip_x is implemented badly. It still iterates over items (calls
+ next_skip n times) and is jit.unroll_safe. This means that the JIT will assume
+ skip is a constant and compile a linear trace unrolling all iterations. This
+ is *BAD*. Instead it would be something like:
+ res.offset = self.offset + skip
+ for views something slightly more complex that does appropriate modulo.
+ Note that next() has unroll_safe, because the loop only dependas on the
+ length of shape which is a constant for assembler.