Problem: Executing a :normal command in 'statusline' evaluation causes the
cursor to move. (Dominique Pelle)
Solution: When updating the cursor for 'cursorbind' allow the cursor beyond
the end of the line. When evaluating 'statusline' temporarily
reset 'cursorbind'.
Problem: When 'cursorbind' is set another window may scroll unexpectedly
when 'scrollbind' is also set. (Xavier Wang)
Solution: Don't call update_topline() if 'scrollbind' is set.
Problem: Computing the cursor column in validate_cursor_col() is wrong when
line numbers are used and 'n' is not in 'cpoptions', causing the
popup menu to be positioned wrong.
Solution: Correctly use the offset. (partly by Dominique Pelle)
