Modified OctomapInterface::deletePoint and KeyFrame::AddKeyMapPoint

Hi Simon and Stephan,

As per my e-mail, I created this pull-request to modify:
1) KeyFrame::AddKeyMapPoint : definition of v2DiffBest for each of corresponding apCurrentBestPoints (center, upperright, upperleft, lowerleft, and lowerright), since it is dependent on the nSourceLevel.
2) OctoMapInterface::deletePoint : add MapPoint specification inside, which was missing previously.

Thank you.


Best Regards,

Giovanni Sutanto