EZP-21035: PHPDoc: synced with service interface
EZP-21035: Optimize: execute code more likely to throw exception first
EZP-21035: Fixed: isSingular() returns false by default

Value was not inverted when method was renamed from isRepeatable()
EZP-21035: Added ContentTypeFieldDefinitionValidationException to addFieldDefinition()
EZP-21035: PHPDoc: hint property type
EZP-21035: Implement ContentTypeFieldDefinitionValidationException for addFieldDefinition(), enable returning validation errors for multiple field definitions
EZP-21035: Removed unnecessary import
EZP-21035: Updated tests
EZP-21035: fixed BadStateException argument name
EZP-21035: move isSingular() check back to BadStateException
EZP-21035: added ContentTypeValidationException
EZP-21035: move isSingular() check to ContentTypeValidationException and BadStateException
EZP-21035: update ContentType controller for added exceptions
EZP-21035: updated tests
EZP-21035: fix passing by reference warning
EZP-21035: updated REST specification
EZP-21035: updated 5.2 BC changes
EZP-21035: new field type method: onlyEmptyInstance()
Fixing some PHPDoc
Test EZP-21035: Cover creating ContentType with more than 1 singular Field