Added tcmalloc as common library; Changed the Centralized Simulation Manager to group objects in a deque rather than a vector
Went back to vector container for object_group_t, instead of deque. The vector seems to offer slightly better performance
Generalized the Individuals, Environment, and DistributedEnvironment to be dependent upon a LCM object (life cycle model); Created specializations of these objects for the default_life_cycle