[2.0] Accomodate joincolumn names in the metadata, in the selection and the hydration processes. Improved Api of the ProxyFactory. Working implementation of lazy loading for *-to-one associations (affects #2348)

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

[2.0] Fixed 4 issues with ProxyGenerator. It was not considering the type hint and it was generating an E_STRICT error with incompatible method declaration. Some cosmetic changes in Query

[2.0] Updated semantical error to display token and text close to the found error. Some cosmetics applied.

[2.0] Fixed issues discovered during code coverage report generation. Made all ClassMetadata properties public (good reasons, read the class docblock). Performance improvements.

[2.0] Moved code between Query and AbstractQuery. Added first NativeQuery implementation. Hydration work and code movements for discriminator column usage. Started implementing Single Table Inheritance.

[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).

[2.0] Parser work. Added double-dispatch functionality to AST node classes for use in the SqlWalker to reduce big if/else instanceof checks and for better maintainability. Also its less error-prone in the SqlWalker because its harder to miss a conditional case. Added new extensible DQL function implementation.

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

[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>)