Get an old pool in a synchronized block

It has race condition if it is placed outside of the block.
Changed to refer $HOME instead of $HOME_DIR

$HOME_DIR is not defined in everyone's environment.
Read all of defined global configuration

singleLineMode, printUnprocessedStackTrace and stackTraceDepth were not
loaded by scalikejdbc-config.
Read poolConnectionTimeoutMillis

connectionTimeoutMillis is deprecated.
Fixed a test that occasionally fails
vesion 2.0.0-beta3