Andrew's pitchfork: Schiff, modified Schiff + warning lines

Currently the software allows drawing regular Andrews Median Lines only.

Please add other Median Line types:

- Schiff
- Modified Schiff

You can find more information about the Schiff and modified Schiff median lines here: Schiff and modified Schiff

It would also be great to be able to draw warning lines

It would be absolutely great to have these tools implemented :)