Removed support to imbricated query added yesterday (which fixed ticket #782). The same thing could be easily achieved without need of Doctrine support, as mentioned in comments. Dev team decided to drop this support for now, but are considering for 1.0

started refactoring to final mapper structure for 1.0. different mapping strategies are factored out as separate strategy classes instead of inheritance.

Merged r3518:r3700 from branch to trunk. Branch to be deleted, soon. Development continues in trunk.

reverting the reorganization done in 3455-3456 in order to make merging my experimental branch to trunk easier.

Preparation for new organization of code in to sub packages. Changed autoload() to work with new structure.

Introduced a new attribute ATTR_AUTOLOAD_TABLE_CLASSES that can be used to control whether Doctrine should try to autoload custom table class files when looking for them.

More refactorings. Commented out the plugin tests for now. They seem to wreak havoc with a lot of other tests (especially validator tests) and i havent found the reason yet.

Makes it easier to see the dependencies between these two concerns, cache the results of the query parsing process later on, implement & use alternative hydrators to experiment with different algorithms etc. etc.
Other small refactorings.

--no commit message