Unity Enlighten does not bake lighting into sprites. This script reaplace (temporarily) every sprite in the open scenes by a mesh this will trick Enlighten to bake the lighting for each sprite, afterwards you can call a function to transfer all the ligth data into the original SpriteRenderer.
This code supposedly works if you have any external lighting solution, but is not tested yet.
Pull Requests are welcomed!
Use at your own risk, be smart and create a backup of all your work before using this code !!!
I mananged to get the bake working with sprites packed using the new SpriteAtlas. To experiment with this feature use instead of using Lighting/Prepare Sprites in step 3 call the Lighting/Export Packed Meshes, let the editor do his thing, them folow the steps as usual. Notice that it may look strange outsite the play mode but will look right as soon as you hit play.
Limitations:
Please set the Sprite Packer mode in "Edit/Project Settings/Editor" to be "Always Enabled"
You can see it working by open the scene demo scene an following the steps above. The demo uses a modified version of the 2D Platformer.
Latest Unity builds changed the Sprites-Diffuse shader and removed the ligthmaps support, the new shader Custom/Sprites-Ligthmap adds this function back. Thanks Coresi7 for pointing it out and for providing the shader.
The baked lightmaps have too much redundant parts, this causes alot of video memory been used for the same parts of the static lighting. A possible fix for this maybe combine all the meshes into a single one, then spliting into multiple squares,