Native UI instead of Qt

[Klaim]

At some point it will be necessary to switch UI to native api instead of relying on Qt. There are several reasons to this, mostly to make sure people on both Mac and Windows are in known terrain when using the UI.

I'm not sure if it's necessary to totally drop the Qt view, but it would make one less target to work on.

Before doing this I have to:

• setup the strong isolation (see Back-end/Front-end isolation #1 )
• see what is the right API to use on Windows (there are several now, and one is more oriented to Windows 8)
• provide UI design documents to drive the effort

I started a discussion for this (but you can comment here): https://groups.google.com/forum/?fromgroups=#!topic/aos-dev/1q9FmKg0I8k

[Klaim]

Depends on #1