Memlet stride optimality overlay

An overlay for the global view, which highlights memlets in red, where the striding is suboptimal with respect to a given data layout.

E.g.:
with `A = int[N, N]`:
```Python
for i in range(N):
    for j in range(N):
        A[i, j] += A[j, i]
```
One of the memlets in the resulting map accesses a contiguous dimension, and one does not.