Refactor the code: using fabs()
Fix conflict comment in code.
Fix conflict comment in code.
Speedup: removing best customers in crossover.
Add some comments in mutation.
Refactor the code: insert entire rank in environmental()
Remove useless comments.
Add *.exe to .gitignore
Rename two functions...

solution::isSame → solution::operator ==
solution::sort → solution::operator <
Add "modified" flag for each route to speed up fitness function.