Doc - Pull out instructions for setting up development environments for Maemo and Symbian, to reuse the topics in Nokia Qt SDK documentation (with if defines)

- sprites_combined was too old (pull from Qt)
- page.png asset was not copied and used
- style.css was improved
  - don't show bullets for numbered lists
  - vertically center <img>s in ul or ol environment
  - don't specify widths for the module name

Reviewed-By: Leena Miettinen

The spacing errors come from Qt, and should be fixed there.

Reviewed-By: Oswald Buddenhagen

Reviewed-by: Leena Miettinen

Reviewed-By: Leena Miettinen

Reviewed-By: Leena Miettinen