Commented Task: Remove dependency on System.Data.Entity.dll [1262]

There are still some places in the designer where we use System.Data.Entity.dll. We should remove this dependency. Note that some of the dependencies are "soft" - i.e. we use type name as a string. Those need to be investigated and removed if possible.
Comments: Fixed in #7b3f034 in the designer repo LoosingTurfWar - removing dependency on System.Data.Entity.dll from all designer projects but versioning facade (Fixes https://entityframework.codeplex.com/workitem/1262) * Removing references to System.Data.Entity.dll from EntityDesignModel.csproj and EntityDesign.csproj * Removing src/EntityDesign/VisualStudio/ModelWizard/*.* which were not part of any project * Moving codegen related files to src/EntityDesignerVersioningFacade/LegacyCodegen * Making codegen related files internal as they don't have to be public * Refactoring legacy codegen related classes to remove code duplicaton and allow at least some level of testing