[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] 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.

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