Commit 6be5471 switched FreeListRef to use FreeListObjectAlloc underneath, but didn't accound for the extra memory that is needed to store the reference count directly after the object payload. The possible implications of this are memory corruption and memory leaks, although with the predefined allocator setip, this will only happen to types with a POT size or slightly less.
This commit adds an "EXTRA" template type parameter to FreeListObjectAlloc that is used to determine the additional amount of allocated memory, which is set to "int" in the case of FreeListRef.
(cherry picked from commit d78a9ce89b845e4f89a84bd70bbd48c7595463d4)
(cherry picked from commit 613d15926e241c03e75bb2d237d39ba712613aeb)
The library is able to support simple TCP servers in the current state. The API is still mostly compatible with mainline vibe.d, but the driver systen has been replaced by the eventcore library and sockets/files/timers/... are now structs with automatic reference counting instead of GC collected classes. The stream interfaces have been removed for now.
