Changes:
- Added new command: tc_highlight
  Highlights various objects in the game world.
  Right now only blocks can be highlighted.
  
  Syntax:
    /tc_highlight block <duration> <x> <y> <z>
        <duration> is in seconds. Maximum 10.
        <x> <y> <z> is a block position.



Changes (internal):
- Refactored the ClientProxy class TO HELL.
  Created a whole bunch of new classes.
- Added class shutter to script engine.

Fixes:
- Fixed the bug that the 'Paste'-Tool wasn't working.
- Fixed the bug that the URL is not shown in the 'Confirm Open Link' dialog
  when opened by the URL-Block.

WIP:
- Started working on a new VoxelBrush called 'Voxelator'
- Started working on a in-game file browser.

Script: list_all_entities
-------------------------
// Lists all entities (name and position) except players.
entities = world.getEntities("@e[type=!Player]");

for (var i = 0; i < entities.size(); i++) {
    var entity = entities.get(i);
    out.println(entity.getName() + " @ " + entity.getPosition());
}
