Rebuild: memory_policy, now we have stable and elastic options.

[dakingffo]

MPSC_queue<int, stable<256, 64, 2>> queue;

This is a queue that does not free memory during runtime(when number of MPSC_queue instance > 0).
This pattern use old architecture, but we also rebuild global_manager.
thread local capacity: 256
alignment: 64
memory expasion factor: 2

MPSC_queue<int, elastic<256, 64, 2>> queue;

This is a queue that will free memory during runtime.
This pattern use new architecture. we are designing it.
thread local capacity: 256
alignment: 64
load factor: 2 (The maximum ratio of the number of producers to the number of chunks that triggers the release process)