Add more problem functions in fitness.py

[Agrover112]

Add more problems rel to current flightscheduling problem. (No matrix problems) Only problems whose solution is of the form: [1,2,3,4] OR [x1,z2..........xn] and corresponding domain : [(-a,b),(-c,-d).......nth-tuple]. Refer fitness.py for existing problems and cost functions and their domains.

Ideally the isse requires you to add a sample cost function to solve a particular problem, whose inputs are of form 1*n