Added schema creator interface.
added database exception.
implemented schema creator.

no longer dependent on the tenant.
added mysql driver
added postgres driver
added sql server driver
Added TenantException
added connection methods and props
defined the tenant repo interface
made arrays optional input
implemented the SchemaCreatorManager
implemented tenant repository.
added configuration directives.
added missing config directive.
pulled in code from previous code base.
Added some query builder stuff to base repo
updated various repositories.
added tenant model modifications.
Ported artisan commands

moved the artisan commands from the old code base. still need to update
namespaces and make sure all features work with the new classes (some of
them have changed)
service provider registers schema manager