* all camke module files are now in simox/CMakeModules
* FindBullet also uses Bullet_DIR to detect bullet
* Simox checks whether Bullet uses single or double precision
* removed the option SimDynamics_USE_BULLET_DOUBLE_PRECISION
* Set default for Simox_BUILD_SimDynamics to true (a warning will be printed if bullet is not found and SimDynmics will not be build)