Added a PaddleInput ABC and a corrosponding implementation for mouse input.

That implementation is controlling the location for both paddles at the
moment.
Added score counting based on wall collisions in the PaddleGameState.
The LocalServer now sets a paddle's destination to it's initial position.

This is only done in the LocalServer::createPaddle function.
No need to set the destination to the initial position anymore.
Removed all orientation code, leaving only vertical mode supported.
The Label is now templatized to allow for storing any content type.

The content is converted to a string with boost::lexical_cast when
generating the surface cache.
volume.cpp Node.hpp and ObjectManager.cpp now include the algorithm header.

Gcc was complaining while clang wasn't which is why it got this far
unnoticed.
Labels now render the calculated score.
Label::getSurfaceWidth and Label::getSurfaceHeight are now surface_width and surface_height respectively.
Added a mechanism to queue object creation and deletion in the LocalServer.

This is for collision observers and the like to use so that further
collision detection and response don't fail mysteriously when an object
is failed to be found, etc. Queued actions are handled in
LocalServer::step before any physics code runs.
Server::getObject, ObjectManager::findObject, and Quadtree::findObject have all been renamed to find_object.
No need for LocalServer::createPaddle and LocalServer::createBall.

Now there are two functions in Object.h which aid in constructing either
type of object: make_paddle and make_ball.
No need for the specialized insert functions in the ObjectManager.

They weren't even being used.
setObject in the ObjectManager and Quadtree is now set_object.
Removed the various insertion helpers like makePaddle in the Quadtree class.

They weren't even used.
There is no reason why the ball retains a 'forces' velocity.

Old code. No use for it now.
Server::setVelocity and Server::setDestination are now set_velocity and set_destination respectively.
The raytracing function now follows constraints but doesn't react until the object is completely done moving.
No need for the common/ prefix in an include by volume.h.
Added two new functions to volume.h.

One finds the center point of a given volume while the other finds a
vector that represents the direction from one volume center to another.