[2.0] Some work over SchemaTool update of schema (affects directly the CLI schema-tool task on --update option.

[2.0] Refactored classloader architecture. Renamed ClassLoader => GlobalClassLoader. Introduced IsolatedClassLoader that is suitable for participating in autoload stacks. Added 2 example entity classes to the sandbox with 2 xml mappings and 2 yaml mappings. Simplified sandbox setup.

[2.0] Removed xdebug builtin support from Debug::dump(). Added run-dql CLI Task. Updated tasks to wrap Exceptions thrown and diplay nicely. Fixed bug with CLI that ws incorrectly splitting strings into an array instead of consider them raw.

[2.0] Fixed test case. All in-memory changes should be flushed before querying. That's how it works in other ORM tools too

[2.0] fixes #2478 Now PersistentCollections may contain NEW elements and track policy monitor them when flushing on DEFER_IMPLICIT mode

[2.0] fixes #2478 Add/persist/retrieve was doubling the resultset of collection is solved. It was a merge in PersistentCollection creation. I am not 100% sure it is the right patch, but it works and does not break any other unit tests

[2.0] Added missing connect() call in Connection:quote, which was throwing E_FATAL when using DQL. Thanks Damon Jones for the report