Profile mk3: Curve output

Слиты nikitronn запросил слияние profile_curves в master

Created by: portnov

This adds Curve output to Profile Mk3 node. Socket contains a separate Curve object for each profile segment (i.e. each statement). They may be concatenated using Concat Curves node.

https://gist.github.com/bb38f4595a8299e86d817c5720a57a97 Screenshot_20200530_234137

Preflight checklist

Put an x letter in each brackets when you're done this item:

  • Code changes complete.
  • Code documentation complete.
  • Documentation for users complete (or not required, if user never sees these changes).
  • Manual testing done.
  • Unit-tests implemented.
  • Ready for merge.