make addons blender versions consistent

finished

Previously we had three versions, Select/Deselect, Select or Deselect, and (De)select, choosen the third (shortest) one for now.

* Remove api info, this is not used anymore. 

- Check for keymap availability to suppress warning messages when running
  blender in background mode

indentation edits and copy pyrimid from contrib (where I had made some edits), removed so this wont happen again.

Plus a few styling enhancements.

[[Split portion of a mixed commit.]]

[[Split portion of a mixed commit.]]

- remove unused imports
- remove/comment unused vars
- fix for some bugs with unused vars being used

- replace line intersection function with mathutils one.
- snap to edge intersection works with object  transforms now.
- clean whitespace

from perfection cat (sindra1961)