Bug in simd exercise

[pkestene]

Hi,

I think there is a bug in simd_warp exercise:

data is a 2d View declared with the default memory layout, but it really should be declared with LeftLayout, so that memory is contiguous along extent(0).

I think the error was not seen because the input is initialized with constant data, and consequently the bug is neutral; but if you initilialized with non trivial data, one can see that the final result of test_simd and test_scalar are not the same.

I can provide a small fix for that if needed.