Added mip-maps to text for better 3D quality.

- The mip-maps are renderered by re-rasterizing the text on each
mip-map, to have the crispier look as possible.
- The better quality in 2D with one-to-one pixel is without mip-maps.
- But when scaled or zoomed the text is far better with mip-maps.
- Corrected the TestSpyceDisplay.