Stack overflow when spec files are in sub folder of .grunt without sub folders

[lukeapage]

I found that when I put my spec files in .grunt/grunt-contrib-jasmine/sub folder I got a stack overflow exception here:
https://github.com/cloudchen/grunt-template-jasmine-requirejs/blob/master/src/template-jasmine-requirejs.js#L102

that code looks pretty suspicious - not sure what it does - I debugged and essentially this:

grunt.file.expand({
        filter: 'isDirectory',
        cwd: "C:\path\to\repo\.grunt\grunt-contrib-jasmine\sub-folder"
    }, ".")

was returning []

[lukeapage]

maybe related to #60