Distributor and Collector objects moved to Storage

Restructured code so the (Atom|Group)(Distributor|Collector) objects are
now members of the (Atom|Group)Storage classes instead of the configIo
class.  This required doing the associating/initializing/allocating of
these objects only once inside the simulation class.  As a result of
this, specifying the parameters (atom|bond|angle|dihedral)CacheCapacity
inside the parameter file will no longer do anything.  These parameters
have all been hardcoded to 100.
For the sake of brevity, and consistency with the GroupDistributor, pleae call the accessor functions of AtomStorage that access the AtomDistributor and AtomCollector simply "distributor()" and "collector()". It is clear that they are accessing the AtomDistributor and AtomCollector simply because they are member functions of the AtomStorage.