makes event listener callbacks execute asynchronously

[rovolution]

Background

After diving through our source code and tests, I realized a serious issue...none of our event listeners were executing asynchronously!

Though we were exposing a callback based API, the callbacks were being executed synchronously whenever the private method _trigger() was being executed.

I wrapped the callback invocations in setTimeout() with a timeout of 0 (which cues the callback to be invoked on the next event loop tick) and fixed a bunch of our tests to reflect this.

Pull Requests

Please accompany all pull requests with the following (where appropriate):

• [x] unit tests (we use Jasmine 2.x.x)
• [ ] JSFiddle (or an equivalent such as CodePen, Plunker, etc) or screenshot/GIF with new feature or bug-fix
• [ ] Link to original Github issue (if this is a bug-fix)
• [ ] documentation updates to README file
• [ ] examples within /tpl/index.tpl (for new options being added)
• [x] Passes CI-server checks (runs automated tests, JS source-code linting, etc..). To run these on your local machine, type grunt test in your Terminal within the bootstrap-slider repository directory

[jespirit]

For future reference:

setTimeout() with delay of 0. Under Late timeouts: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setTimeout#Reasons_for_delays_longer_than_specified

[rovolution]

@jespirit Thanks for the review! i updated with feedback. take a glance and let me know if it all looks good.

[rovolution]

@jespirit just removed the changes + removed the default timeout amount of 0 in the unit tests (setTimeout defaults to 0 seconds when a specific timeout is not specified)

[rovolution]

@jespirit feel free to make the changes you want if you don't want me to block you. i probably will not have time to work on this