add a mode without graphics

[Max-RM]

add a mode switch so that the amulet can work without displaying the world space, but at the same time it retains the ability to edit the world database through plugins. this will be useful for PCs that do not support opengl 3.0

[Max-RM]

yes, I know that Amulet may have support for such PCs in the future, but still such a switch would be useful to load the PC less. it may be useful in some situations.