== some wiki urls fixes ==

- fixed url in add_mesh_gemstones.py, the page existed 

- created pages with a gentle "to-be-written" warning where needed
  and fixed urls in:
  - add_mesh_archimedean_solids.py
  - io_mesh_stl/__init__.py

  See:
  http://wiki.blender.org/index.php/Extensions:2.5/Py/Scripts/Add_Mesh/Archimedean_Solids
  http://wiki.blender.org/index.php/Extensions:2.5/Py/Scripts/Mesh/Surface_Sketch
  http://wiki.blender.org/index.php/Extensions:2.5/Py/Scripts/File_I-O/STL
  http://wiki.blender.org/index.php/Extensions:2.5/Py/Scripts/File_I-O/Camera_Animation

Not nice to send people to non-existing pages :)