Initial Build Setup: define compilers and configs

We must admit: we still couldn't get a proper build output yet. Our system is old, fragile, and every attempt so far has ended in frustration. My system is old that the only game I can play is SFG Soccer! That's why every contribution here is priceless.

This issue will track the Initial build setup for OLSRT:

• Decide on compilers (GCC/Clang/MinGW).
• Clone the repository.
• Add OLSRT to your project.
• Add first minimal example (e.g Async Hello World, Event Loop, and etc...).
• Document build steps in README.

Contributions are extremely valuable here. Even the smallest PR (fixing a bug, adding MakeFile, writing a test) will make us very, very happy.