*Title: The ability to input placement of attribute in class.

*Documentation:
The ability to input placement of attribute in class into the input fields 
instead of moving attributes up and down inside a class.
The system checks on input if there is no attributes with the same placement 
and stores new values if ok. When storing defined version of a class it sortes 
attribute by given placements and assignes new placements from 1 and up (1,2..n).