Basic overloadable operator() for fitness methods
utilizing new bit walking based iterator
Added iterators for free_list states
Added in free_list masking elements
Added couple of asserts to verify that elements have not exceeded the list
Corrected template argument lists. Fixed comparison operator definitions to use self_type. Added bit_walking based iterator
Added fitness update operator definitions for basic_allele
Added unittest for bit_walker based iterator
Made reproducePopulation a templated function which accepts a PopDist object. Added in discrete_distribution for population calculation based upon computed fitness. Changed fitness calculation to utilitize fitness_method definitions. Fixed div_by_zero error in fitness calculation