Although not yet released, I am trying to make sure that committed versions are runnable (especially stable branch), so if you want to test out the system, simply follow the installation instructions. Note that the function definitions are still subject to change, but any rooms you build should be compatible with later versions.
I am currently diverted from the main work on LPortal, trying to get some kind of lightmapping working in Godot for a demo. It turns out the current lightmap workflow is quite broken. I've spent several days trying to work around bugs in the version of xatlas godot is using, but with no luck, so I'm now going to resort to exporting a mesh from godot, unwrapping in blender, then reimporting back into godot.
This means a slightly more complex workflow, but it does potentially allow baking lightmaps in blender which should lead to a nicer result. The downside is that I won't have a bake for dynamic shadowing as objects move through the level.
The standard non-baked dynamic lighting workflow is mostly working (if not perfectly optimized), and that may be preferable for most people on desktop, but it is my intention to create a highly optimized system that will run very fast on mobiles as well, allowing fast action 1st person shooters etc.
