Using unique type for id fixes some warnings.

Changed the base class from PointWithID to MathPoint. Also introduced a
std::size_t _id for the id of the Node.

This change saves 8 bytes per MeshLib::Node because the Node is not anymore a GeoObject.

Since MinimalBoundingSphere uses MathLib::Point instead of GeoLib::Point.

Conflicts:
	GeoLib/Point.h

[DataExplorer] automatically load a file given as a command line argument

for version information. Dummy version 6.6.6 is set.

Update more copyright years to 2012-2015.

Updated copyright year to 2015

PETSc corrections

Cleanup