* BD2.Common/Extensions.cs:
  Added method te return the first object in an IEnumerator<T>

* BD2.Core/Database.cs:
* BD2.Frontend.Table/Index.cs:
* BD2.Frontend.Table/Transaction.cs:
* BD2.Frontend.Table.Model/Relation.cs:
* BD2.Frontend.Table.Model/IndexBase.cs:
* BD2.Frontend.Table/TransactionSource.cs:
* BD2.Frontend.Table.Model/FrontendInstance.cs:
  
Small changes to "Relation" and "IndexBase"
* BD2.Frontend.Table.Model/Row.cs:
  Removed parameter to match the new method signature.

* BD2.Frontend.Table/Relation.cs:
  Made it actually usable.

* BD2.Test.Frontend.Table/Program.cs:
  Removed a sample that required a private database that I don't have
  the right to publish to run.