Upgrade pip to 1.5.6
Issue #21362: concurrent.futures does not validate that max_workers is proper
Miscellaneous corrections and updates to the OS X README file.
Miscellaneous corrections and updates to the OS X README file.
support pep 3118 format strings for ctypes objects with nontrivial shapes (closes #10744)

Patch by Matti Picus.
merge 3.4 (#10744)
Issue #20186: memoryobject.c: add function signatures.
Issue #21430: additions to the description of non-blocking SSL sockets
Issue #21430: additions to the description of non-blocking SSL sockets
(null merge 3.4)