gl3n: port from the old vector code to gl3n
whitespace: kill tabulators
ode: initialize ODE
cmake: turn on -Wall
gamemanager: fix fallthrough warning
warning: use static for constant values in classes
CentHead: have subclass mark themselves as "ready"

The invariant() section is invalid until the end of the ctor, so guard
against it until the subclasses have completed construction.
gamemanager: fix escape and pause keys
gamemanager: add a TODO item for replays