Constructers in place and other updates

Constructors created for the various types of createable objects most
internal methods implemented outside of update methods, need to replace
player mesh with new one that isn't sinbad.  Missile still needs its
base mesh, collision detection, and detonate functions coded.  Time
tracking for spawning and scaling in place, just needs missile spawning
code.  Shells for movement implementations in place awaiting sorting out
getting a player on screen.  Some PowerUp fields not assigned in
construction as those should be determined by the PowerUpAgent.