Merge branch '1.3.x'

* 1.3.x: (65 commits)
  Clarify deprecation block for same-namespace resolution
  Add BC layer for optimized collection operations
  Updated existing tests for CollectionPersister for tracking executed queries where it is required. Added missing tests for checking simultaneous embed-many collections updates under different storage strategies.
  Simplified methods for working with nested collections, remove redundant checks
  Merge remarks implemented.
  Reduced complexity of CollectionPersister::excludeSubPaths method.
  Updated CollectionPersister logic for handling nested collections scheduled for update - now nested collections for one parent is updated inside one query where it was possible.
  Added check for sub-paths before collections removal in CollectionPersister::deleteAll. Fixed style of code.
  Implemented CollectionPersister::deleteAll method for simultaneous deletion of collections that is belong to one document.
  Deprecate GridFS features
  Deprecate proxies from doctrine/common
  Finish renaming dirtyCheck methods
  Remove usage of deprecated ClassMetadataInfo class in hydrators
  Renamed scheduledForDirtyCheck
  Removed PHP 5.5 workaround
  Add changelog for 1.2.6
  Fix wrong type hint for generator type in ClassMetadata
  Fix serialisation of uninitialised PersistentCollection instances
  Deprecate indexOptions argument in SchemaManager (doctrine#1910)
  Deprecate dropDups option on indexes (doctrine#1910)
  ...

docs/en/reference/aggregation-builder.rst

@@ -75,9 +75,9 @@ the aggregation builder.
             ->expression(
                 $builder->expr()
                     ->field('month')
-                    ->month('purchaseDate')
+                    ->month('$purchaseDate')
                     ->field('year')
-                    ->year('purchaseDate')
+                    ->year('$purchaseDate')
             )
             ->field('numPurchases')
             ->sum(1)