Add in cut/copy/paste functionality

[boaromayo]

[boaromayo]

I'll start the cut/copy/paste process for tiles by:

• First having the selected tile be inserted into the clipboard.

• The selected tile is based on where the map's mouse cursor is located at.

• The tileset panel will then select that tile, sort of like how the eyedropper tool works in paint programs.

• If cutting, I'll also have the tile removed from its location (set tile to blank, not null) after the tileset panel points to the selected tile.

I'm also thinking of adding in a "Select Area" option if the user wants to have an area cut/copied/pasted.

I'll also have to look in to how other editors, such as Tiled, implement this feature.

[boaromayo]

According to this answer, it seems I'll have to enable Serialization on the Tile and Map objects before I start working on the process since it's not as simple as transferring an object from one memory address to another.