An attemp to create a terminal text editor

Followed kilo tutorial.

• EditorLib: contains some attemp to create a library? Interfaces to Editor's data structures.
• Editor3: I suppose 3 means the third attempt. Have some Terminal interface. Documented code. Looks cool, though it's not OOP. I followed kilo mostly.
• Editor3WithoutTabs: experiment to eliminate real and render parts of line representation. Probably, it works.