Added new GUI elements for ticket #471
New sets of icons triggered by ticket #471
Added some comments to implementation of ticket #471
Added missing files to implementation of ticket #471
Created branch for ticket #471 Implemented basic GUI features ready for implementation testing and documentation.
Implemented ticket #505 "Integrate Perlin noise"
Fixed issue #556 "Cut, Copy, Paste in context menu of refactorer not working"
Implemented ticket #470 "Add 2D structure detection"
Implemented ticket #549 "Improve editing functionalities of the terminal"