Import is_int() from ctk.
Fix the vim modeline; set tw=0.
Implement crude_error_message_test().
Fix the dest for --no-svnmucc.
Make is_int() handle None seamlessly.
Fix component_depth().

Decorator order was the wrong way around, and v.isdigit() was getting called
against non-int values.
Fix crude_error_message_test() variable reference.
Implement ensure_blocked().
Fix test logic (tests now pass).