backend cleanups (licence, SvGenericNodeLocator..)

[zeffii]

Some operators are called from buttons which are located in a Blender UI space which does not track the context.node, (the origin of the click is undefined). The node.wrapper_tracked_ui_draw_op wrapper is an alternative for those nodes that do need extra origin tracking - the wrapper passes the node's node.id_data.name and node.name behind the scenes. Most nodes don't need this, until they do.

This PR commits a few backend cleanups

• makes operators that do need to track the click-origin use SvGenericNodeLocator mixin, this simplifies the transition away from idtree and idname. These are some of the oldest variable names in sverchok :) it's time they get more obvious names

self.idtree    -> self.tree_name
self.idname    -> self.node_name

along the way i'll also change a few node license blurbs to the abbreviated version.

---

• ...sverchok\nodes\list_mutators\multi_cache.py
• ...sverchok\nodes\logic\evolver.py
• ...sverchok\nodes\logic\genes_holder.py
• ...sverchok\nodes\network\file_path.py
• ...sverchok\nodes\scene\objects_mk3.py
• ...sverchok\nodes\solid\export_solid.py
• ...sverchok\nodes\svg\svg_document.py
• ...sverchok\nodes\viz\viewer_waveform_output.py
• ...sverchok\utils\sv_3dview_tools.py
• ...sverchok\utils\sv_obj_baker.py
• ...sverchok\utils\sv_operator_utils.py
• extensively tested