Merge pull request #204 from dantleech/query_builder_odm

Query builder odm
edge case fixes
totally refactored the ClassMetadata class to store all mappings in a single array
Merge pull request #216 from doctrine/refactored_classmetadata

totally refactored the ClassMetadata class to store all mappings in a single array
Added $qb->expr()->descendant('/path/to/parent');