Event Spies: Added functions to check call counts

Jasmine equivalents:
`.calls.any()`
http://jasmine.github.io/2.0/introduction.html#section-23

`.calls.count()`
http://jasmine.github.io/2.0/introduction.html#section-24

Example tests:

    var spyEvent = spyOnEvent('#some_element', 'click');

    // Passing
    expect(spyEvent.calls.any()).toEqual(false);
    $('#some_element').click();
    expect(spyEvent.calls.count()).toEqual(1);

    // Failing
    expect(spyEvent.calls.any().toEqual(false);
    expect(spyEvent.calls.count()).toEqual(0);