Use application.conf for Slick settings.

- The system properties scala.slick.ansiDump and scala.slick.dumpPaths
  become config keys slick.ansiDump and slick.dumpPaths.

- slick.ansiDump is enabled by default in testkit/test.

- Drivers get their own Config object. This can be used in the future to
  enable driver-specific features that require a certain database
  version or configuration.
Add BoneCP support to Database.forConfig.

The configuration is very similar to Play’s. The new JdbcDataSource
abstraction allows 3rd-party connection pools to be supported easily.
JdbcBackend.Database gets a new method `close` for shutting down a
connection pool.