Update qunit path

when doing a fresh install `npm install`  and then running `npm test`,  the command fails with this error

    lincolnhawk:JsonDiffPatch lholmquist$ npm test

    > jsondiffpatch@0.0.7 test /Users/lholmquist/develop/projects/JsonDiffPatch
    > qunit -c ./src/jsondiffpatch.js -d jsondiffpatch:./src/jsondiffpatch -t ./test/test.js


    Testing /Users/lholmquist/develop/projects/JsonDiffPatch/src/jsondiffpatch.js ... { [Error: Cannot find module     '../node_modules/qunit/support/qunit/qunit']
    message: 'Cannot find module \'../node_modules/qunit/support/qunit/qunit\'' }
    npm ERR! weird error 1
    npm ERR! not ok code 0


Looks like the qunit folder structure has changed a little bit