Add BYTEPATH tutorial

Add a new section for the [Lua](https://www.lua.org/) programming
language and a new section for the [LÖVE](https://love2d.org/) 2D game
engine. Inside it add a tutorial for creation of a complete 2D game with
**Lua** and **LÖVE** called
[BYTEPATH](http://store.steampowered.com/app/760330/BYTEPATH/) by
[SSYGEN](https://github.com/SSYGEN).