Sink heating

[themikelau]

Type of PR:
Implement ability for sink particles to heat gas particles within softening radius.

Description:

• Luminosity of point mass is specified via the ilum column. A new column, imass_enclosed, has been added to store the mass enclosed within twice the softening length, 2*hsoft.

Testing:

• Observed reasonable stability of star with a sink-particle core radiating at the stellar luminosity, with radiation transport turned on.

Did you run the bots?
No.

[danieljprice]

@themikelau this should be ready to go. I cleaned up a couple of things in test_eos so please check everything is ok from your side (in particular I made a helper routine to avoid the repeated code to setup the rho, T grid; since the choice seemed arbitrary I made the limits the same for both, unless there is a reason you wanted different limits tested for idealplusrad vs. hormone?)

[themikelau]

@danieljprice Thanks for cleaning up test_eos. Your changes are fine if the test passes.