Scaffolding for plBullet

CMake Additions - watch out for hard coded paths!
Create BTSimulationMgr

Some basic class work, and registration with plasma
Create plBTPhsyical

Some work to start plBTPhysical
plBTPhysical::Read

Initial reader for plBTPhysicals based off previous plPXPhysical
Controls for plBTSimulationMgr

Create and use a Instance Key, and add some control to plBTSimulationMgr
plClient additions

CMake changes to wire plClient with libs and some more plasma
registration work. Bullet.log should appear in the log view
Merge pull request #1 from DarK501/bullet-prototype

Initial Plasma Wiring :: bullet <-> bullet-prototype