Drop singleton

[peter-gribanov]

Fix for Don't write to global functions.

Singleton is a anti-pattern.
You change a global config() function to a global instance of Configuration class.
This is very, very bad.

[TomasVotruba]

I'd keep it simple with 1 example to do things. That would keep point more clear.

[TomasVotruba]

I like the singleton-drop change.

[piotrplenik]

Yes - I agree to drop singleton, but with one example only.

[peter-gribanov]

@jupeter i can restory singleton examle and mark it as bad.

[peter-gribanov]

I add bad Singleton example and remove YAML config.

[TomasVotruba]

@peter-gribanov Could you decouple the singleton example to standalone item?

[peter-gribanov]

@TomasVotruba I create a new section. You can complete the description.

[TomasVotruba]

Thank you, this is good enough