120 removing blue lines in ors tool

[merydian]

Removes the blue lines every time the red X button is clicked.

[koebi]

Steps to reproduce artifact blue lines:

1. Open Plugin
2. Click "+"
3. Add Points (closing the plugin automatically and creating blue lines)
4. re-open plugin (since it got closed)
5. click "+" button, resetting points but keeping blue lines

[koebi]

LGTM - I fear that this will come up again at some point, but that will hopefully mean that someone has reproducible steps, and we can fix it then :)