Changed GameCore constructor to set mode variable first to avoid a
null-pointer in Renderer(line-80) when attempting to access it. 
This doesn't seem to be a problem on Windows, and it seems to still
happen on linux arbitrarily, launching from sh/teminal with/out optirun
all seem to eitehr work perfectly or hit this nonsensical nullpointer, I
hope this is just a problem with my laptop's Optiumus setup.