Better README usage documentation

[WalkerKnapp]

The current README Usage section is very lacking. It currently says:

Devolay aims to be close to the original NDI SDK while still following Java standards and conventions. The vast majority of applications can be simply translated from NDI SDK calls to Devolay calls.

Examples can be found in examples/src/main/java/me/walkerknapp/devolayexamples.

This is lacking because we don't explain the exact differences between using the NDI SDK in C++ and using Devolay.

If possible, I would like to turn this into a section that can:

• Introduce Devolay to users who are new to both this project and the NDI SDK in C++
• Give detailed explanations for how to translate code from C++ to Java.

[WalkerKnapp]

Additionally, it would be great if we could provide more detailed instructions or examples for integration into android projects. It's a complicated subject, and I can see many situations where there would be demand for better instructions.

(i.e., for @chenguo123456, feel free to talk about instructions for Android platforms here. I don't do support via email, but you can ask anything to be included in the documentation here)