[2.0] DDC-169 - Fix build, Postgres, Oracle and Sqlite made some minor troubles with regards to sequences.

[2.0] DDC-169 - Converted introspection queries of all platforms to return Column, Sequence, Index, ForeignKey Schema Instances instead of arrays, heavily pimped Oracle support thereby.

[2.0] DDC-169 - Finalized implementation of Schema diff algorithm, added diffs of sequences and foreign keys. Fixed several bugs and changed the API of the Schema objects.

[2.0] - DDC-169 - Fixed another regression in refactored SchemaTool, began porting of eZ Components Database Schema Comparator, SchemaDiff and TableDiff.

[2.0] - DDC-169 - Refactored lots of sections with duplicate code in gather relations part of SchemaTool::getCreateSql()

[2.0] - DDC-169 - Completed refactoring of SchemaTool::getCreateSql() to use new DBAL Schema API, several internal optimizations in SchemaTool are now possible. Stripped out shared functionality with getUpdateSql() so that this part of SchemaTool is still completly working with the old API.

[2.0] DDC-169 - Savepoint for Refactorings in Schema-Tool - It is now generating DDL according to the old and the new mechanisms in parallel. Equality of generation has been verified on Sqlite, Mysql, Oracle. If Postgres is also verified, the old code will be removed in favour of the new one completly.

[2.0] - DDC-169 - Added DropSchemaSql Visitor - Refactored Visitor package a bit, however its still not very appealing to have that much use statements cluttered in the code

[2.0] - DDC-169 - Added DropSchemaSql Visitor - Refactored Visitor package a bit, however its still not very appealing to have that much use statements cluttered in the code

[2.0] - DDC-169 - Began refactoring of DBAL code, introduced object notation for a database schema, including Tables, Indexes, Constraints, Sequences and Columns. Added a CreateSql Visitor which transforms a schema object graph into the required SQL statements to create it. Next: Replacing SchemaTool::getCreateSql() with new syntax...

[2.0][DDC-164][DDC-165] Fixed. Cleaned up ManyToManyMapping. Cleaned up identifier handling and handling of composite identifiers in some places.

DDC-127 - Special Case with invalid input parameter in DQL leads to php notice instead of an exception.

DDC-126 - Make Query, NativeQuery Fluent-Interfaces for all their set Methods, renamed setExpireQueryCache() and setExpireResultCache() to expireQueryCache() and expireResultCache(). Updated UPGRADE_TO_2_0 document accordingly.

DDC-127 - Enhance IterableResult by making it implement the Iterator interface, wrote a unit-test for this scenario, also added some additional tests for special cases in the query api that lead to exceptions.

[2.0][DDC-158] Small correction to previous patch. Moved takeSnapshot up in order not lose new objects that were added before initialization.

[2.0][DDC-158] Fixed. Collections did not take snapshots after lazy initialization leading to wrong change sets.