Test point in element

Introduces extension of the Element-interface by adding a method ```bool isPntInElement(GeoLib::Point const& pnt)``` that will return true if the point is located either inside or on the boundary of the element and false otherwise.
For line-elements it tests if the point is located on that line, for 2D elements the point needs to be coplanar with the element nodes and located inside the 2D element.

This introduces a little redundancy to the current Face-interface (i.e. Tri's and Quad's) where already a method ```isPntInside(pnt, eps)``` exists which basically does the same but allows to specify an additional epsilon. Currently, I have left this method as it is. Should I remove it?
sorry i'm not getting why derived classes have a default value while the base class doesn't have it. I'd understand it if it's opposite way because we use the base class more often. Actually I think it might be better to delete all default values in both base and derived classes, because we always calculate eps from given nodes and should use it consistently for all geometric calculations.