->quoted() method so that file and directory names can be exported to the shell

[bcowgill]

would be useful if a ->quoted() method was provided so that:
"this dir/this file.name" would be returned as q{'this dir/this file.name'} or q{this\ dir/this\ file.name}
"this dir's/this file.name" => q{'this dir's/this file.name'} or q{'this\ dir's/this\ file.name'}

so that all shell special characters were escaped or quoted.