New: add editorconfig file

[yisibl]

We need better basic text formatting.

[puzrin]

Let's keep repo clean. Modern editors detect indent good enough.

[yisibl]

If this project wants more people to participate, then I think this configuration file is essential. This is almost standard for open source projects.

[puzrin]

I understand your position, but in real world this will not change too much, because font generation topic is too complicated.

I'd prefer return to this later, when more people request this.