Add README with basic troubleshooting tips to the Blinky example

[rogerdahl]

[pfalcon]

Thanks for the patch! But there're 2 issues even on the surface: contributed files uses overlong lines, which makes them not readable and not maintainable, and the fact that there're files, instead there should be one file and one commit for it.

Beyond that, there're deeper issues. This would be about one millionth "basic troubleshooting tips for esp8266" on interwebs. All incomplete, some confusing. For example, what Mac users will do with/about "sudo usermod -a -G dialout `"?

esp-open-sdk's approach has always been simple: it's a script to build a toolchain. Most other parts are handled by other sites/projects.