DB::beginTransaction assert()-ing

[SchaichAlonso]

Currently, TinyORM is asserting no other transaction on the same connection is in partially commited state when beginTransaction is invoked.

However, the Q_ASSERT statements are disabled when QT_NO_DEBUG is defined during compilation, i.e. when compiling in release mode. If TinyORM needs it's consumers to explicit distinction between top level transactions and truely nested transactions / savepoints, exceptions provide a more reliable error handling mechanism then assertions do

[silverqx]

This is true, this is one of the first code I wrote and it should be completely refactored to exceptions, i know about this here .