"t" and "Shift+t" are Lua bindings in common.lua
Maybe needs to be part of SettingsEngine instead, but the display code was already in RenderEngine, so it'll do for now on this branch
Disable SGCT ESC terminate handling and implement a method that optionally waits before closing the application (closing #120)
- ESC key is now bound to a call to "openspace.toggleShutdown()" that will initiate a shutdown in 3 seconds unless ESC is pressed again
- The countdown timer is set in the openspace.cfg
