spawnmenu.AddContentType
Description
Registers a new content type that is saveable into spawnlists. Created/called by spawnmenu.CreateContentIcon.
Arguments
2 function constructor
A function that is called whenever we need create a new panel for this content type.
It has two arguments:
Panel container - The container/parent of the new panel
table data - Data for the content type passed from spawnmenu.CreateContentIcon