Fix Connection option config parsing

Also refactors the ConfigurationTest class. Removed strict checking of default_commit_options (and tests), added missing options. Fixed handling of readPreferenceTags option for XML.

As a change, "server" and "options" no longer have default values; however, existing code in Configuration should handle this fine.
Clean up XML and YML config fixtures
Use boolean config type for "auto_mapping" option
Update XSD to match Configuration class
Do not skip tests if mongod, PECL driver, or ODM is unavailable
Fix name of "annotation" mapping driver type
Test profiler options in full configurations
Handle "metadata_cache_driver" namespace option

This is currently supported in AbstractDoctrineExtension.
Only prepare "metadata_cache_driver" string values before normalization