Remove warnings

```
/Users/trsw/github/hirb/lib/hirb/formatter.rb:105: warning: shadowing outer local variable - klass
/Users/trsw/github/hirb/lib/hirb/helpers/table/resizer.rb:51: warning: assigned but unused variable - v
/Users/trsw/github/hirb/lib/hirb/helpers/table.rb:305: warning: method redefined; discarding old max_fields
/Users/trsw/github/hirb/lib/hirb/helpers/table.rb:315: warning: method redefined; discarding old width
/Users/trsw/github/hirb/lib/hirb/view.rb:130: warning: shadowing outer local variable - e
/Users/trsw/github/hirb/lib/hirb/view.rb:143: warning: method redefined; discarding old render_method
/Users/trsw/github/hirb/lib/hirb/view.rb:256: warning: method redefined; discarding old config
/Users/trsw/github/hirb/lib/hirb/menu.rb:92: warning: assigned but unused variable - helper_class
/Users/trsw/github/hirb/lib/hirb.rb:58: warning: method redefined; discarding old config_files
/Users/trsw/github/hirb/lib/hirb.rb:72: warning: method redefined; discarding old config
```