DDC-536 - Make forwards compatible change in EntityRepository adding getters for the protected variables to allow a smooth change when they will be turned private in Beta2

[DDC-497][DDC-500][DDC-342] Fixed. Persister polishing and refactoring. More to come for that, but after beta1.

[2.0] Fixed and added some missing/wrong docblocks. Renamed Assigned to AssignedGenerator as scheduled to be renamed.

[2.0] Code cleanups. Preparations for DDC-193. Fixed DDC-399, type configuration remains global for now but the irritating instance methods on the Configuration have been removed. Use Type::addType et al. Added TODOs for naming standards.

[2.0][DDC-362] Fixed missing namespace declaration on __call method of EntityRepository. Thanks Marcel Walter for the patch.

[2.0][DDC-234] Fixed issue with EntityRepository that was not considering alias of root Entity when instantiating a new QueryBuilder

[2.0][DDC-122][DDC-97][DDC-98][DDC-147] Refactored metadata mapping drivers by removing the useless PRELOAD mode. Introduced ClassMetadataFactory#getAllMetadata. Classloader simplifications. Old classloaders deprecated. New Doctrine\Common\ClassLoader is almost the same as the previous IsolatedClassLoader.

[2.0] Fixed PHP Notice in SchemaTest (only variables should be passed by reference...) and a few other cosmetics in various parts.

[2.0] Fixed several referential integrity issues. Fixed critical issue with inserts being run twice on postgresql/oracle. Added support for additional tree walkers that modify the AST prior to SQL construction and started to play with it in a testcase.

[2.0] Fixed issues discovered during code coverage report generation. Made all ClassMetadata properties public (good reasons, read the class docblock). Performance improvements.

[2.0] Started to implement proxy object handling. Introduced a configuration switch for partial objects (allowPartialObjects) that defaults to TRUE. Setting to FALSE enables proxying and lazy-loading.