Adds the PushModes Try and Wait to allow producers to specify how they want to push their data to the queue if the queue is full.
If the queue is full:
- Try will fail to push to the queue, returning false. Try only returns true if it successfully pushes to the queue. This may result in items not being pushed into the queue.
- Wait will wait until a slot is available to push to the queue, resulting in potential for deadlock if a consumer is not running.
While this is the primary change, we also:
- Remove the mpsc namespace and rename Queue to MPSCQueue
- Make Slot a private struct within MPSCQueue
- Remove the AlignedAllocator template argument, as we use std::allocator
- Replace instances of mask + 1 with capacity, and mask + 2 with capacity + 1
