entity: prevent updating primary property in save() method
update: added tests & typo
custom: fixed invalid argument
FindAll: limit and offset must be always an integer
Revert "FindAll: limit and offset must be always an integer"

This reverts commit bdce6c74957acc01ff09f02082494a6d8ced0acf.
queries refactoring
tests: entity test refactoring
repository: better queryOn() exception with unknown entity
entity: support for readonly properties [closes #47]
first commit