* add pkg/stdlib/objects Length function
* rename lenght.go -> length.go
* fix tests according to other tests
* add new tests to length tests
* delete objects method Length
* add objects method Has
* add objects function Keys
* small fixes in Keys and Has functions
* change Has function
* unit tests for Keys function
* add unit tests for merge. also little change in lib.go
* add doc to Keys function
* Merge function prototype
* add unit tests for KEEP function
* added KEEP function
* added doc for KEYS function
* update lib.go
* update lib.go
* upd merge prototype
* addded isEqualObjects function to objects tests
* change object method Compare
* added unit tests for Compare method
* changed Compare method
* fix Compare method
* rename method Clone to Copy
* added Cloneable interface
* added Value to Cloneable interface
* implemented Cloneable intefrace by array
* added some more unit tests for values.Array
* fix values.Array.Compare method
* added one more unit test
* implemented Cloneable interface by Object
* unit tests for Object.Clone
* move core.IsCloneable to value.go
* change Clone function
* move IsClonable to package values
* updated MERGE unit tests
* added MERGE function
* added MERGE to lib
* added one more test
* changed MERGE function
