[2.0] DDC-169 - Finished ALTER Table TableDiff refactoring, adding code to handle index and FK changes. Added a general functional test for alter table against all platforms.

[2.0] DDC-169 - AbstractPlatform::getAlterTableSql() now accepts only a TableDiff instance as argument across all platforms.

[2.0] Fixed DDC-63 and DDC-106. Oracle tests for SchemaManager need further tweeking, marked as skipped for now.

[2.0] Fixed DDC-103 - Platform::getAlterTableSql() should return an array on all platforms, added doc-blocks on all methods and fixed some.

[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] Test coverage for OFFSET AND LIMIT sql generation for all platforms and Query class with setFirstResult() and setMaxResult()

Ticket: 766,767

reverting the reorganization done in 3455-3456 in order to make merging my experimental branch to trunk easier.

Preparation for new organization of code in to sub packages. Changed autoload() to work with new structure.

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