Kaz Okui

Ref #32 I understand that #32 is closed, but not sure that's because it's hard to do async stuff, or supporting block, or both. I'd like to use block based...

I added observation to MAKVONotification so that I can remove observation from a block like this: ``` swift course.addObserver(nil, keyPath:["progress", "contentDownloaded"], options:nil, block: {(note:MAKVONotification!) in switch note.keyPath! { case "progress":...

I ran into an issue that using `addObserver:keyPath:options:block:` causes memory leaks even after calling remove observer method.

There's a bug in Xcode Preview when you have a multi-platform project. When you set build destination other than iOS on preview in such project, Xcode Preview tries to build...