Wiki page: Coming From C++

[Jakob Ovrum via Digitalmars-d]

Thanks for the feedback, I think I've incorporated all the 
suggested changes.

Also added a section on how D deals with object slicing.

I can't seem to get the compiler to error on dangling else. I 
tried the examples in the original PR[1], but they seem to 
compile without error with DMD 2.067. Is anyone able to make the 
compiler error on dangling else?

[1] https://github.com/D-Programming-Language/dmd/pull/336