Use Arbitrarily dimensioned arrays in rust.

Note: Although I've tried to keep implementations as fast as possible, constructors are O(d^2) and indexing is O(d) where d is the number of dimensions, and n is the sum of the magnitudes of all dimensions.

Usage

```rust // Create a 4d array of u32s. // where the dimensioning is 5x3x9x2 let mut my_array: NArray = NArray::new(4, &[5,3,9,2]);

// Set some arbitrary point (getting is the same, but no = 9) my_array[&[3, 1, 5, 1]] = 9;

// Create a 3d array of u32s where each index // value is the sum of it's index coordinates // with dimension 5x8x11. let myfancyarray: NArray = NArray::fromfunction(3, &[5, 8, 11], |n: &[usize]| { n.tovec().iter().fold(1, |acc, &item| acc*item as u32) }); asserteq!(myfancy_array[&[3, 4, 9]], 108);

```