#847: prepare for using connection as context mgr#886

Closed

tseaver wants to merge 3 commits intogoogleapis:masterfrom tseaver:847-connection_as_context_mgr-setup

+360-332

Commits on May 27, 2015

Move threadlocal stacks of batches to relevant connection module.
tseaver
committed
Move 'get_connection()' convenience APIs to subpackage __init__.
tseaver
committed
Move '_require_connection' def into related '_implicit_environ' module.
tseaver
committed