Revert part of 16c46114 to fix race
condition that incoming stream after sending GOAWAY causes connection
error.  The strict stream handling introduced in the above commit does
not handle several cases well (e.g., GOAWAY race, and refusing streams
because of concurrency limit).

std::make_shared in Xcode 7, 7.1, and 7.2 does not perform
value-initialization, and causes undefined behaviour if struct does
not have user defined default constructor.  This workaround explicitly
defines user defined default constructor, and initializes values.

As suggested in GH-674

This commit also fixes the bug that SETTINGS timer continues after
connection was closed.

This script prints out the commit author from `git log` output.  Used
to update AUTHORS file.