Add test for INSERT … SELECT

Test for amphp#89.

Fix ConnectionConfig key map

The key map was not being used prior.

Update example

Update to tagged amphp/sql and amphp/sql-common

Do not set $this->promise on connection creation

Ignore connection push if pool closed

The server going away may cause it to send an error packet

Fixed amphp#40 - unpack not having enough input

Prepared statement closing must properly reset the sequence ID

Update connect() and crypto enable