Use async/await instead of callbacks

[ChrisK91]

I created a branch to see if I could get async and await working (see branch async-await). I used them to implement a image loading Task, and they seem to work fine. I suggest that we move from the current callback scheme into an async await pattern. async and await are easier to read, making it easier to edit code written by others. It also minimizes (or eliminates) cross thread access.

Here are some other advantages: http://stackoverflow.com/questions/7870334/await-async-vs-classic-asynchronous-callbacks

[the-eater]

I tried creating the await stuff but I found out that it didn't work so thats why there is an callback system go rambo on it :+1: