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

[2.0][DDC-22] Fixed. Also cleaned up association handling. More to come: exception refactorings, proxy simplifications (single proxy class, not two).

[2.0] Streamlined result structures. Hydration improvements: Small overall improvements, large improvement for (joined) fetched collections (~60%). 

[2.0] More cleanups for recent lazy-loading implementation and minor object hydration improvements and cleanups. Collection refactoring part I for ticket #2352.

[2.0] Accomodate joincolumn names in the metadata, in the selection and the hydration processes. Improved Api of the ProxyFactory. Working implementation of lazy loading for *-to-one associations (affects #2348)

[2.0] Introduced SQL logging facilities. Made Type constructor private to prevent instantiation and force use of the factory method getType().

[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.

[2.0] Moved code between Query and AbstractQuery. Added first NativeQuery implementation. Hydration work and code movements for discriminator column usage. Started implementing Single Table Inheritance.

[2.0] Refactored SQL query building process and hydration. Hydration should now support result sets with any number of root components. Introducing ResultSetMapping that is used by hydration instead of queryComponents. This allows mapping of arbitrary SQL queries (NativeQuery).

Fixed paths that were referring wrong namespace resolution.
Implemented more Parser and AST classes: JoinVariableDeclaration and Join.
Fixed wrong semantical checks of IndexBy grammar rule. They should be in IdentificationVariableDeclaration and JoinVariableDeclaration.