The flip function is now being tested in Volume_Tests.cpp.
Added a few helper functions to volume.h: constrain and find_direction.
The constrain function from volume.h is now being tested.
The find_direction function from volume.h is now being tested.
New render function to render a given percentage of some volume sides.
Added some keybindings in PaddleGameState to render constraints and slow down the simulation.
The Quadtree will not attempt to reinsert an object into the quadtree if it didn't belong to any node.
The toggle to slow down the pong simulation is now implemented in the main game loop.
Crashing now yields a JSON game data dump.

In addition the file streaming is now offloaded to a function:
pong::dump which takes a filename a Json::Value.
The physics code now works reasonably well with a constrain-based system.