[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] Refined implementation and semantics of the merge and detach operations. General cleanups and API improvements. Added a testcase for detaching/serializing->unserializing->modifying->merging to demonstrate the transparent serialization.

[2.0] Changed identifier quoting strategy to something simpler. Dropped Doctrine prefix from annotations.

[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] 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).