Addition of print_stacktrace() for debugging
Addition of -std=c++11 in compile instructions
Addition of print_stacktrace() for debugging
Shift to range for(), copy protection, const

Changing from explicit use of iterators to use of range for() loops
where possible
Adding copy protection to guard against unintentional copying for the
heavyweight classes: Chromosome, Genome, Population, Subpopulation
Adding const in further locations for safety and to prevent
unintentional copying