Make default projection dir consistent between svg export and cq-editor

The svg export and CQ-editor Isometric preview doesn't have the same direction direction, which is confusing.

Code example:

```py
import cadquery as cq
from cadquery.cq import Workplane as WP

fig = WP('YX').box(5, 5, 5).union(WP('YX').circle(1).extrude(15))

cq.exporters.export(fig, 'fig.svg')
show_object(fig)
```

Svg export and CQ-editor preview: