Added a simple monitoring framework for Terasology.
Refactored chunk state representation into its own class.

+ added class ChunkState
- removed subtype Chunk.State
* changed class Chunk to use the new class ChunkState
* changed some other classes to use the new class ChunkState

* changed protobuf implementation to simplify encoding/decoding of chunk states

- removed default constructor for class Chunk
- removed implementation of interface Externalizable for class Chunk

Note:
From now on, java object serialization for chunks is no longer supported!
Merge remote-tracking branch 'origin/stackable-chunks-2' into monitoring
* adapted calculation of player position for class ChunkMonitorDisplay
Implemented chunk monitoring.

* extended class Chunk to support chunk monitoring
* added some convenience methods for events to class ChunkMonitor
Show monitoring window at startup.
Added support for threads monitoring to class LocalChunkProvider.
Added support for threads monitoring to class LiquidSimulator.
Added support for threads monitoring to class TerasologyEngine.
Added support for tasks monitoring in class TerasologyEngine.
Moved content of package performanceMonitor into package monitoring.
Added some more info to thread monitoring for class ThreadMonitorPanel.
Extended terasology monitor gui to display performance monitor values.

+ added class PerformanceMonitorPanel which displays all performance monitor values
* adapted class TerasologyMonitor to use the new performance monitor panel
* little gui tweak for ThreadMonitorPanel
Some internal changes to class PerformanceMonitorPanel.
Extended class ThreadMonitorPanel to show the number of errors and the error class and message for each thread.
Added configuraton options for monitoring to the advanced settings screen.

+ added button to enable/disable advanced monitoring (does not yet work...)
+ added button to show/hide the monitoring window at startup
* extended class AdvancedConfig to support these two options
Slight tweak for displaying the monitoring window at startup.
Added support for mouse-dragging to the class ChunkMonitorDisplay.
Moved handling of creation and display of the advanced monitor into a new class called Monitoring.

* renamed class TerasologyMonitor into AdvancedMonitor
+ added new class Monitoring
* changed class TerasologyEngine to use the new class Monitoring
Added missing return statement to class Monitoring.