[2.0] Implemented more TODO items in DQL Parser. Optimized PathExpression. Changed wrong grammar rule name in EBNF.

[2.0] Changes in DQL grammar for optimization purposes. Implemented new DQL grammar rules and did a couple of TODOs

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

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.