rigidbody operators poll functions were mixing up CTX_data_active_object/ED_object_active_context.
- replace ED_operator_rigidbody_add_poll with ED_operator_object_active_editable_mesh
- replace ED_operator_rigidbody_active_poll with ED_operator_scene_editable for operators that use the entire selection.
- remove rigid-body from objects that are converted from meshes to curves, while this isnt crashing it is confusing to see in the UI.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55918 954f8c5b-7b00-dc11-b283-0030488c597c