Wrong order of tables in evolutions

Order of tables in evolution's SQL file is sometimes incorrect. This happens if tables are linked together and named in specific way.

You can use Slick's `++` method on `DDL` object to concatenate DDLs together. This way Slick knows dependencies between tables.

http://slick.typesafe.com/doc/1.0.0-RC2/lifted-embedding.html#data-definition-language

I've added test that fails if DDLs are not concatenated by Slick.