Snlite newnode operator

Слиты nikitronn запросил слияние snlite_newnode_operator в master

Created by: zeffii

this allows the user to spawn a new scriptnode directly from the open TextEditor,

  • it will fill the scriptnode with edit_text.name
  • it will call node.load()
  • it will position the node at the center of the currently open nodeview.
  • keymap ctrl+shift+return