* New category: 'Import/Export'

now in the Object category.
*note this cleans Add_Mesh so only add_mesh scripts are in that category.
part of add mesh clean up for adding recall function.

* Cleanup up some PEP8 stuff.

* Renamed image_to_planes() to planes_from_images()
* Fixed some strange code that overwrote extList.

* Fixed "url" and "descrioption" in bl_addon_info
* Made this into a "Add Mesh" script (not "Object"), since that is what it does.
* Renamed some internal functions to make it easier to guess their functionality.
* Reformatted the code a bit and updated/fixed some comments.

-added missing mesh_update and select/active states

script is good to go.

[[Split portion of a mixed commit.]]