Unintuitive output from line co-ordinates

A very minor change request, as it is fairly trivial to work around it externally, but could the driver normalise/re-order co-ordinates internally. Looked at intuitively the following should output 2 lines joined in the corner of the display, but does not in practice.

```
hagl_draw_hline_xyx(display, 32, 0,  0, colour);
hagl_draw_vline_xyy(display, 0,  32, 0, colour);

```

