population geometry container and 3d visualization thereof

[emuller]

Implement a class which describes the 3D geometry of a population of cells

Implement wdigets to visualize the geometry using hardware acceleration (OpenGL, etc.), and visualize SpikeList and AnalogSignalList objects associated with the network.

The widgets should be embeddable in a larger GUI framework which works with a network architecture/ datacontainer query language (see ticket:48).