Release version 1.15.8.1-4

Fix Travis no-sse42 builds

Fix Windows image build and pin to 2016. Appveyor/Travis improvements

Fixed an error caused by '"' in executing apt (openresty#95)

fix travis file again

Upgrade LuaRocks to 3.1.2 and change release URL (openresty#100)

Upgrade Openresty to 1.15.8.1rc2

Upgrade to OpenResty 1.15.8.1rc1

Stop with SIGQUIT so that "docker stop" is actually a graceful stop (o…

…penresty#80)

Updated AUTHORS