Update deletion-related features of `CreateCtrl`

* I added JSHint W106 exception to `app/scripts/controllers/Create.js`.
* I refactored `deleteClass` function of `CreateCtrl` controller.

    * I added `tidyArray` function which manipulates an array, and deletes the elements of array which a check function passed with returns `false`.
    * I added `isPropertyNotEmptyArray` function which returns a function that checks if the value of a property of `this` object is not an empty array.
    * I added `eachThis` function which returns a function that calls `callback` function for every element of `this` object.
    * I added `saveStoredClassCart` function which stored the object `storedClassCart` to cookie.
    * I added several error functions to use in deletion-related functions.

* I added functions to delete a major entity, or a course entity from `classCart` and `storedClassCart`.
* I modified the test spec for `CreateCtrl` controller to be more specific.