Typed D allocators based on Google Thread caching memory allocators

[Basile B. via Digitalmars-d-announce]

This new DUB package uses the "Thread Caching" memory allocators 
from Google performance tools to make typed D allocators, conform 
with the interface defined in std.experimental.allocator.

- Posix only.
- TCMallocator (= Mallocator).
- TCAlignedMallocator (= AlignedMallocator).

And maybe more (TCMMapAllocator TCCAllocator).

about Thread caching memory allocators:
http://goog-perftools.sourceforge.net/doc/tcmalloc.html

the repo:
https://github.com/BBasile/tcmallocd

PR and BR obviously welcome if you see an error.