Added 2 new GUIs:
- NPC's GUI to see a list of NPC and convert them to constructor by right-clicking on them (/constructor npc)
- Schematic's GUI to load a schematic or a structure that you want and building it with the default values of building (/constructor list)
Also fixed the fact that the constructor was placing block of air without the ignoreair value, it will fill with block of air only if you have turned both values ignoreair and excavate to true.
And now, the constructor will continue to build where he finished after a reload of the server or a restart.
That's all, have fun!