support escape character for white space in running single test case with option -t or -f

in case of having test cases like `exports['test case']`

I am not able to use either `-f` or `-t`
`nodeunit tc.js -t 'test case'` as space is delimiter and it looks for folder instead
`Error: ENOENT, stat '/Users/xxxxx/test/case'`

Please let me know if there is existing options to escape , and please support `\` as espace char white space. quite trivial but I think helpful.Thanks.