Added test cases for AgentTest

Along with moving forward, AgentTest will now also examines staying
in place and turning. testSees() changed so that it can check if
an agent can see behind itself.
Fixed turning bug
JAXB loaders are now capable to load/save using streams.
Added pause, resume functionality and default configuration loading.

By clicking the Start menu item on the GUI when no simulation is
created, it tries to load the default configuration found in the
resources. Pause menu item will make the simulation thread wait
for notification sent when Start clicked or on exit. Also, loading
methods in the Game class will not start the simulation after creating
it. That can be done with the startSimulation() method of the Game
class.
Added preCalc() method for neurons.

Neurons had to calculate their values multiple times in the same
world step. To speed up the simulation, neurons can now use the
preCalc() method, which is called only once in each world step,
to calculate and store their value, then return the stored number
in getValue() method.
Implemented food incraese.
Fixed bug in EyeNeuron.preCalc(), added high bound for food.
Added GameWorldTest and GameTest unit tests
Configuration for checkstyle
Cleaned up code
Removed EyeInputNeuronTest, as the class is mostly tested in AgentTest
Implemented SwingView.error()
Synchronized lists in GameWorld to avoid concurrent access.
Fixed bug in Game.saveSimulation()
World descriptors are now filled when a new world is created.