Ticket: 194

Ticket: 192

fixing #172 - copying a record now will set non-null fields to modified so that when it's saved it inserts correctly

Ticket: 150

Ticket: 150

Necessary changes to the validation components. Further improvements and docs will follow in the next days.
Ticket: 150

- validators codes are now string instead of integers (constants)
- validating is now handled in record level
- added new component Doctrine_Validator_ErrorStack
- new methods Doctrine_Record::isValid() and Doctrine_Record::getErrorStack()
- errorStack now as a record instance variable

Major change on how transactions are being handled: insert / update queries are now executed immediately and only deletes are being gathered (due to delete optimization strategies). Fixes #138, #135

Added new exception classes, renamed Doctrine_Repository to Doctrine_Table_Repository, refactored many classes

Ticket: 132

Ticket: 134

Ticket: 133

Ticket: 131

Ticket: 129

Ticket: 128

Ticket: 126

Ticket: 125

Ticket: 101

- Lazy connections possible through Doctrine_Manager::addDSN($dsn, $connectionName). Connections will then be opened automatically when they are requested the first time.

Changes concerning multiple connection control:
- injection of the Connection object into the Doctrine_Table constructor, instead of a static lookup.
- added optional Connection parameter to save/delete of Doctrine_Record and Doctrine_Collection

Refactored Doctrine_Connection: separated into two different classes Doctrine_Connection and Doctrine_Transaction

Doctrine_Record::getID() -> obtainIdentifier()
Doctrine_Record::setID() -> assignIdentifier()