Pycrud

* Added: null supported with QueryInfo.from_json

* Added: `is` / `is_not` supported

* Note: renamed to **pycrud** in pypi (thanks for owner [Emanuel Calso](https://github.com/bloodpet/))

* Fixed: don't execute update or delete if select nothing from database

* Fixed: contains_any

* Added: negated condition supported

* Added: QueryInfo.from_json multiple same operator supported

* Added: invalid `on_event` define will cause Exception

* Added: empty update values now throw exception

* Fixed: ability inherit bug

* Fixed: update with unary operator filtered by perm

* Added: `is_` and `is_not` for field

* Added: unary operator for values: `array_extend` `array_extend_distinct` `array_prune_distinct`