removed BlockWipedAllocator

The BlockWipedAllocator was never actually 'switched on' for any jobs and its design would not work in the threaded framework anyway. Thread-safety checks (static and runtime) were showing this class to be a problem so we removed it.
More changed related to the removal of BlockWipeAllocator

Removed the include of the no longer existing header file. _bqueue_item no longer inherits from BlockWipedAllocated<_bqueue_item<T>> which doesn't change any behavior since the extra facility was never used.
Removed use of LocalCache and made function local static thread safe

The class LocalCache was intended to work with BlockWipeAllocator but the latter was never actually used. Since LocalCache was only ever used in this one file, we removed it and replaced it with an std::auto_ptr which is what LocalCache was actually internally using.
Merge pull request #1729 from Dr15Jones/removeWipedAllocator

Multithreading fixes -- Removed BlockWipedAllocator