Add scrolling to Visual mode
Fix scrolling bugs
Draw cursor when Visual mode
Fix bug that becameHandler or didEndHandler did not call its super class method
Fix display argument string does not call recursivly
Call becameHandler before onCompleteChild
Fix yanking into register does not work.
You always have to use self.yankRegister instead of _yankRegister
in evaluators because yankRegister calls parent evalator recursively
and get actual register
Delete unused codes
Support register in Visual Mode
Support f,F,t,T,;,,