* ADD: more test classes for Softdelete and History
* update reference models after adding test classes
* DbMigration:Improved History generation for sqlserver
* FIX: When DB supports Sql2011 platform, we must not alter the history-table (as this is handled by DB itself)
* DbMigration: When dropping a table, drop the sequence also.
* DbMigration: dropColumn is handled by platformDdl now, as SqlServerDdl needs to delete dependent objects (default constraints...) first
* FIX: DbMigration is not executed on history table
* DbMigration: can drop comment now.
* No effective code change: completed ObjectFactory / fixed imports
* FIX: drop table comment
* Committed the reference models
* REFACTOR: use functions from ddl-help
* NEW: Default values are written to DDL
* fix testcase for sqlserver as default constraints will get names in future
* Reading DbMigration
* ADD: DbmIgrationGenerateTest
* Tables must be created first
* Sanity checks and some getters
* DdlMigration gets applied now
* ADD: Testcase and reference migration scripts
* no effective code changes: add comments
