Defold-box2d Box2D extension

[d954mas]

Add autobuilder CI script for extension.

Native extensions + CI builds

Hello everyone! I’ve just now added a first CI (continuous integration, a.k.a “autobuilder”) script to one of our extensions, extension-websocket. Having such a script makes it easier for us to verify that the extension builds properly for each platform after each commit we make to the repository. It also helps us make sure that the extension builds between Defold versions. The plan is to add such a script to all our supported extensions. The script currently does these things: Find the stab…