Extend "proximity" command to be able to compute the proximity value;
Implement classes for calculate proximity value between two shapes;
Add possibility to set up the number of sample points for the input shapes;
Add tests lowalgos/proximity.
Standard_EXPORT is added in declaration of virtual methods where it was missing, to allow creation of sub-classes in other DLLs.
In some classes in OpenGl package Standard_EXPORT is added for all methods to make these classes usable in other DLLs.
knosulko