Computes i-th point in a Hammersley Point Set of size n

Parameters:

`i`

- index of sample which coordinates we want to calculate

`n`

- number of samples in the point set we are generating

Returns:

`[x,y]`

- i-th point from a Hammersley point set of size n, x and y are from 0..1

```
var hammersley = require('hammersley');
for(var i=0; i<300; i++) {
var p = hammersley(i, 300);
//0 -> [ 0, 0 ]
//1 -> [ 0.00333, 0.5 ]
//2 -> [ 0.00666, 0.25 ]
//3 -> [ 0.01, 0.75 ]
//...
}
```

Based on Hammersley Points on the Hemisphere by Holger Dammertz [2012]

MIT, see LICENSE.md for details.