application flow

1. intro (dom, viewport/viewbox)
2. basic_01_shapes.svg
3. basic_03_opacity_visibility.svg
4. basic_04_animation.svg
5. inter01_embed.html
6. inter02_layeronoff.html
7. inter03_colorpolys.html
8. inter04_mouseover.html
9. brescia/01_mouseover/index.html
10. brescia/02_layer/index.html
11. brescia/03_color/index.html
12. brescia/04_circle/index.html
13. brescia/05_legend/index.html