added an append() method to arrays.
cosmetics.
renamed bokeh test suite to cameras.
implemented a spherical camera, plus many refactorings around cameras.

also:
  - renamed the diagnostic surface shader mode "wireframe" to "screen_space_wireframe".
  - added a new "world_space_wireframe" mode to the diagnostic surface shader.
  - added a #define to switch to 3ds max vector conventions when shading vectors in the diagnostic surface shader.
Merge branch 'master' of github.com:jupiter-jazz/appleseed