converted to meshes, making export fail with empties and armatures.

- can export multiple objects (all selected, not only active one)
- can import multiples stl file at once with the file selector

cosmetic fixes, suggested by Shane Ambler (sambler), thx :)
[#23279] Small cosmetic fix to addons
https://projects.blender.org/tracker/?func=detail&atid=127&aid=23279&group_id=9

this commit also makes a minor change with path joinin in preset_utils.py

* add tests for nodes.
* update poll() usage to be according changes in blender

- cleanup: removed unnecessary options lists

* Now it should _finally_ work as intended.

- mesh_surface_sketch.py
- render_renderfarmfi.py
- space_view3d_align_tools.py
- object_cloud_gen.py

also move bl_addon_info to the top for faster parsing.

These scritps still need changes related to parent classes
- mesh_surface_sketch.py
- render_renderfarmfi.py
- space_view3d_align_tools.py
- object_cloud_gen.py

After discussion with Campbell I've made povray an addon as a package (will remove from bf-blender).
Please roport any glitch or mistake I might have done while porting.

port of script by Jimmy Hazevoet
thanks to ideasman for the noise module.

* Version 0.7.5.2 - Changed callback registration back to original code & fixed bug in there (use bl_idname instead of bl_label)

* Thanks to jesterKing for pointing that out :-)