This patch fix a bug where a rigidbody being also an effector is not updated as other rigidbodies. The UI allows to set both rigidbodies and effectors, so this fix should cause the simulated objects to behave as expected.
Another update loop has to be created in order to avoid simulation instabilities due to rigidbody positions being updated in the same loop as the force computation of effectors in the previous code.
Here is a simulation of rigidbodies that won't move before applying the patch:
Here is a video recorded with the patch: https://www.youtube.com/watch?v=1t2aVjuIURQ
The fix doesn't enable the use of all effectors type with rigidbodies, it only work with some of them. The one that I tested and works are Force, Wind, Magnetic, Harmonic, Turbulence and Vortex.
The ones that were tested and won't work are Boids and Charge. Charge is particularly problematic since it prevents the creation of magnet simulations. Boids are probably failing because there is no way to change the boids specific settings with the UI like for particles.
**update: I fixed the charge effector, here is a video of magnets in Blender using this effector: https://www.youtube.com/watch?v=KsyGjv6OWZI
The code still might need some flags update to take into account effectors moving because of the rigidbody simulation. This is probably the cause for some graphical glitches. Try with a wind force, the arrow is not updated while it is simulating and the lighting is a bit off but the simulation works correctly.