Define target browsers

[AxelDelmas]

It's important to define from the start what our target browsers will be, to have a more precise idea of the scope of our polyfill and the workarounds we are going to implement.

If we want to support IE 9- for example, then we want to have a satisfying degraded version without web workers and that would solve #1 . If we don't care about Safari at all since MSE is in the latest versions, then we can close #1 already

[NicolasWeil]

In the corporate world, where legacy is the daily bread, we still can see browsers like IE8 used by 90% of the end-users, so it might be worth looking at going down to this specific IE version. Not sure about which Flash Player version might usually run on top of it, though.