[2.0] DDC-320 - Fixed Substring across all platforms using AbstractPlatform::getSubstringExpression() instead of the "hand-built" one.

[2.0] Added DQL Functions and Aggregate Functional Test-Case and fixed two small bugs in DQL Parser that came to light, also it seems that some of the functions are not supported by Oracle and Sqlite and some cases of SUBSTRING and TRIM produce bugs on MySQL.

[2.0] Fixed proxy classes to not invoke parent class constructors. We never call constructors to reconstitute persistent entities and proxies always represent persistent entities.

[2.0] DDC-125 - Query Hints are now included in both QueryCache and ResultCache - QueryCache now also uses firstResult and maxResults for the cache key - ResultCache was fixed to use "getSql()" instead of "getDql()"

[2.0][DDC-79][DDC-261] Fixed. Also fixed support for deleting objects by reference (getReference() + remove() + flush()) to effectively delete objects without loading them.

[2.0][DDC-284] Fixed. API polish and some convention over configuration simplifications for join columns and join tables.

[2.0] Fix casing bug in Parser - IfFunction checks lower-case the function name, but register methods don't.

[2.0] DDC-163 - Missing DQL Alias prefix for many-to-many table in SqlWalker lead to duplicate prefix generation in SQL statement when a many-to-many join table is used more than once.

[2.0] DDC-214, DDC-303, DDC-304 - Fix several errors with Schema Inference from Database and Metadata and Comparisons, aswell as related bugs in DatabaseDriver. DDC-305 - Abstracted TRUNCATE command for all platforms.

[2.0] DDC-268 - Exchanged DoctrineException for MappingException and added missing exception method (thanks to Christian Heinrich for the patch)

[2.0] DDC-271 - Add columnDefinition for Join-Column in Annotation, XML and YAML driver, updated SchemaTool to use Join Column definition instead of using the column's columnDefinition if specified. Refactored MappingDriverTest to allow for feature specific test-cases instead of one large assertion block. Fixed typos in XmlDriver - Updated doctrine-mapping.xsd Schema File

[2.0][DC-460] Refactored cache bulk deletion methods to use driver specific features to retrieve list of keys. Also, refactored tests
so that all methods are tested for all drivers.

Removed:

- Doctrine\Common\Cache\AbstractCache::count()
- Doctrine\Common\Cache\AbstractCache::deleteAll()

API Changes:

- Doctrine\ORM\AbstractQuery::getResultCacheId() now public

Bugs fixed:

- Doctrine\Common\Cache\AbstractCache::deleteByPrefix() was deleting _every_ key in cache

[2.0] DDC-277 - Remove support "default" option in metadata mappings, but keep it as a concept in DBAL layer to support for example versionable entities.