Declare World's methods.
Implement World.
Change shared_ptr to unique_ptr.
Move some includes.
Explicit 'auto i' to 'unsigned int i'.
Use emplace_back.
Set Update(int t) virtual pure.
Fix misusages of pointers.
Set destructor virtual.
Fix unused paramaters.
Merge pull request #16 from Neki/topic/hv_world

A basic World class.