malloc and buffer overflow attacks

[russhy]

Allocators should be first class citizen anyways, malloc/free 
should not be used directly, not only they are unsafe, they are 
most of the time not what people need

And i hope what will come out of `std.experimental.allocator` 
won't be using classes..something light, value, extensible and 
made with betterC in mind

It should be the root of everything that comes out of D, not 
something lightly thought

A base to move forward and be future proof