[2.0] Refactored cache drivers. Made use of ArrayCache as the metadata cache during a test suite run.

[2.0] More progress on the DQL parser. Added glimpse() method for the scanner/lexer that is equivalent to peek() immediately followed by resetPeek().

More DQL parser work. First basic WHERE conditions. Changed scanner according to new positional parameter syntax (?<number>)

DQL Parser work. Getting some first tests back running. Reorganizing all parser rules into the Parser itself.

Implemented new classes. Fixed a couple of issues around the road.

Fixes Strict error on EntityPersisterMock.