[Proposal] Unit Testing

[Beliar83]

It is my opinion that testing benefits any programming project. If done correctly in protects against creating and changing code in a way that makes it not work as expected. Unit testing can also be done without any easy way to test the code in the actual program.

A better explanation of unit testing can be found here:

http://gamesfromwithin.com/stepping-through-the-looking-glass-test-driven-game-development-part-1

Therefore I suggest that we take advantage of unit testing as much as possible.

The only unit testing framework for gdscript I found is Gut (https://godotengine.org/asset-library/asset/54),
but it seems to be working fine and has been updated recently. A wiki for it can be found here: https://github.com/bitwes/Gut/wiki