Add mouse support

[TomaszRewak]

So I've spent some time thinking about how may I implement the mouse support for this library and this it the proposal:

• The library will continue to be dependency free and platform agnostic
• The user will be able to easily hook up a library of choice to this framework (for example the MouseKeyHook: https://github.com/gmamaladze/globalmousekeyhook)
• The Character struct will be extended by two fields:
  • Control - the top level IControl that produced this character
  • Position - a local position of the Control from which the character was produced
• Some interactive controls (like a Button) will be able to override the Control and Position fields of characters they are passing through
• The ConsoleManager will be extended with a method that returns a Control and Position values of a specific "pixel".
• A new IMouseListener interface will be added (the list of methods to be decided, but probably OnMuseDown(Position local), OnMouseMove(Position local), OnMoseUp(Position local))
• Whenever an external library detects a mouse input, the user should get the Control and its local Position at the specified global position, check if that control is in fact an instance of the IMouseListener, and call the proper callback.
• The rest is up to the internal implementation of the control

That should keep the interface simple and make it possible to hook up the mouse using one of the already existing projects.

[TomaszRewak]

The basic mouse support has been implemented as shown in the ConsoleGUI.MouseExample project.