[2.0] Fix Fatal errors in unused classes that crash the testsuite when running PHPUnit with coverage-whitelisting of complete Doctrine directory.

[2.0] Parser work. Drafted logic for multi-table deletes through DQL (for Class/Concrete Table Inheritance)

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Added getters to AST. Removed Production::__call. Added visitor support to AST. (guilherme: dont shoot me yet :-). visitor support doesnt hurt even if we do not use it for SQL generation). Lots of other things.

Refactorings and initial commit/draft of new event handling / configuration / bootstrapping. Still need to remove all the static EntityManagerFactory::getManager lookup calls from the Production classes. The production classes need to have access to the EntityManager of the Query that constructed the Parser. It should be injected into the Parser during construction.

Merged all identity maps into one in the unitofwork. identity map now properly works with hierarchies.