Mem alloc again

This pull request adds some custom memory allocation abilities.

There is some documentation on this thread. 

http://discuss.cocos2d-x.org/t/work-to-improve-memory-allocation-and-management-in-cocos2d-x/17442/22

It adds a few types of allocators...

1. global default allocator
2. fixed block allocator
3. global new/delete override allocator or small block allocator
4. pool allocator for pools of object types

Also include tests and diagnostics which can be queried via the console.

See documentation for more details.