Added a headless IDEA run configuration
Made the headless run config use the terasology-server dir as its homedir
Merge #1222 by @shartte - IntelliJ headless run config
Don't print the welcome message multiple times on the server console
Fixes an issue where chunks were never marked as aready after calculating lighting in headless mode, since the headless renderer never called the appropriate method.
Merge #1229 by @sharrte - headless server spawn fix
Merge #1228 by @shartte - headless console fix
Quick fix: make headless try to figure out a default gameplay module / world generator akin to the new gameplay picking GUI