Use smart pointers!

[shahzadlone]

This is a big one! Use RAII styled pointers (smart pointers) where ever necessary.

Get rid of raw pointers! Perhaps a good way to do this would be to find every where new and delete are called to hunt these down (also please use make_unique or '''make_sharedrather thannew``` ( this will be a separate patch I guess.)

Please use unique_ptr unless absolutely need to use shared_ptr.

#23