BT: Fix lock-up & crash in the Elastic Nodes example
BT: Fix lock-up & crash in the Elastic Nodes example

Ensure that we don't divide by 0 when two nodes are exactly on top
of each other.

Reviewed-by: Alexis
Reviewed-by: Joao

pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,KDE/qt,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,igor-sfdc/qt-wk,radekp/qt,RLovelett/qt,radekp/qt,KDE/qt,RLovelett/qt,RLovelett/qt,RLovelett/qt,RLovelett/qt,igor-sfdc/qt-wk,KDE/qt,KDE/qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,KDE/qt,radekp/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,RLovelett/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,KDE/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,RLovelett/qt,KDE/qt,RLovelett/qt,KDE/qt,radekp/qt,RLovelett/qt,RLovelett/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt