Use scalikejdbc-config

Configuration key poolConnectionTimeoutMillis is changed to
connectionTimeoutMillis.
I suppose that it might be just mistake because the documentation doesn't
mention abount poolConnectionTimeoutMillis.
Add lazy for a variable which refers play.configuration
Removed redundant case
Revert to poolConnectionTimeoutMillis
Removed db.global backward compatibility warning
Merge pull request #1 from tkawachi/config

Use scalikejdbc-config