[2.0] Some Annotations parser docblocks, optimizations, etc. Fixed wrong syntax error token report in DQL parser

[2.0] Fixed warning in semantical error reporting (strpos with length over dql length). Fixed wrong grammar rule. Fixed wrong token position on semantical error reporting. Added more semantical checks in UpdateItem

[2.0] Changed structure of creation of SqlWalkers in DQL Parser. They are now strings instead of instances of dummy classes. Implemented nesting level check for ResultVariable

[2.0] InputParameter removed from Literal, since it's not actually a literal value. Changed grammar rules to accomodate this decouple

[2.0] More work on DQL parser of Doctrine 2.0. More semantical checks included. Missing scope checking of ResultVariable (SELECT and Sub-SELECT differences). Removed invalid grammar rules.

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

[2.0] completed implementation of lazy loading for Collections. Created debug helper class. Fixed default for orderBy clause to ASC

[2.0] Finished reorganization of grammar rules in DQL parser source code. Renamed some private methods.

[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).