joesimms: added support for many roots for one table, added another example illustrating this, see EXAMPLE2.tree.php, also changed toString to __toString in getPath()

updated NestedSet to use Zend coding standards.  still a few problems with return values using () that need to be looked at.

joesimms: initial draft for tree support. NestedSet support included, placeholders for other popular implementations also included. Read the README.tree file for more information and changelog to core files. Modified core files have also been included in this commit. hope it works and you like it !

- 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

removing the closing PHP tags form all php files, it\'s not needed and can break sessions which are whitespace sensitive

Many-to-Many relation fetching, fatal proxy state bug fixed, fatal loaded identity map + multiple component fetching bug fixed

--no commit message