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.
There is no longer any reason to have "atomCacheCapacity_", "bondCacheCapacity_" etc. member variables in the ConfigIo class. Please remove these member variables from the class definition and remove the "read<int>" statement that reads them from the parameter file. We should remove them from the file format rather than reading them in and then ignoring them.