IDM: Implement lock-free smart pointers

[elad335]

Replaces std::shared_pointer with stx::atomic_ptr and stx::shared_ptr.

Notes to programmers:

• This pr kills the use of dynamic_cast, std::dynamic_pointer_cast and std::weak_ptr on IDM objects, possible replacement is to save the object ID on the base object, then use idm::check/get_unlocked to the destination type via the saved ID which may be null. Null pointer check is how you can tell type mismatch (as dynamic cast) or object destruction (as weak_ptr locking).
• Double-inheritance on IDM objects should be used with care, stx::shared_ptr does not support constant-evaluated pointer offsetting to parent/child type.
• idm::check/get_unlocked can now be used anywhere.
• idm::find_unlocked has been removed, idm::withdraw and idm::remove_verify now have unlocked overloads with std::true_type.

Misc fixes:

• Fixes some segfaults with RPCN with interaction with IDM.
• Fix deadlocks in access violation handler due locking recursion.
• Fixes race condition in process exit-spawn on memory containers read.
• Fix bug that theoretically can prevent RPCS3 from booting - fix id_manager::typeinfo comparison to compare members instead of memcmp which can fail spuriously on padding bytes.
• Ensure all IDM inherited types of base, either has id_base or id_type defined locally, this allows to make getters such as idm::get_unlocked<lv2_socket, lv2_socket_raw>() which were broken before. (requires save-states invalidation)
• Removes broken operator[] overload of stx::shared_ptr and stx::single_ptr for non-array types.

[Darkhost1999]

Do you need testers for performance now?
Or should performance differences be subtle? With 124 files changed we're testing for any change from the master branch or what should we look for?
I see it merged as I was typing.