[2.0] Fixed issue with functions accepting subqueries. Implemented missing Expr\Join class. Added Expr::*join helper functions.

[2.0] Unified xml/yaml driver mapping tests so that there is a stronger enforcement on keeping them synchronized feature-wise.

[2.0] Fixed several referential integrity issues. Fixed critical issue with inserts being run twice on postgresql/oracle. Added support for additional tree walkers that modify the AST prior to SQL construction and started to play with it in a testcase.

[2.0] Some code reordering, changes. Removed classMetadata from RangeVariableDeclaration, since it is against AST concept.

[2.0] Removed AssociationMappings from ResultSetMapping  for improved caching. Fixed caching issue with reflection classes and properties. Reimplemented and leaned up broken identifier quoting. Added support for named (native) queries. Fixed small hydration memory leak.

[2.0] More docblocks. Renamed methods Type::addCustomType to Type::addType and Connection::exec to Connection::executeUpdate. Added Type::hasType.

[2.0] Added more missing docblocks. Implemented a double-inclusion listener prevention in EventManager

[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] Streamlined result structures. Hydration improvements: Small overall improvements, large improvement for (joined) fetched collections (~60%). 

[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.