Reorganize example names

[ktoso]

Based on public reception, people were immediately opening up the "simplest name" looking one, and then taken aback by the low-level JNI bridging full of unsafe code and cdecl etc. We should make it clear that those examples are just that: low level and raw jni examples, as compared to other ones using swift-java interop.

It should be easier to discover the swift-java example, because that provides a better first impression, and long term user experience.

[timsneath]

Some examples of where this is causing confusion:

• https://news.ycombinator.com/item?id=45700413
• https://forums.macrumors.com/threads/developers-can-now-make-android-apps-with-apples-swift.2469840/?post=34251556#post-34251556
• https://www.reddit.com/r/mAndroidDev/comments/1ohdrfu/comment/nlo53ww/

It's unfortunate because readers who see these comments will have a false perception of the wonderful work the Android Workgroup has done here. I'm hoping that reorganizing these examples can draw attention to the true ergonomics of this for an author of business logic.

[marcprux]

Agreed that this reorg will be useful for clarification.

We should also flesh out the README a lot more, but that can be saved for a future PR.

[ktoso]

Thanks folks; yeap we can keep polishing readme and examples more afterwards still

[andriydruk]

Not sure this example should be listed under “Examples using raw JNI without generated bridging sources”

native-activity - a complete native Android activity with OpenGL ES rendering, written entirely in Swift.

It looks like it needs its own separate section.