This is a trivial test case for the RT debug scheme: swift needs to be compiled
with `--with-rt=debug`. The example generates initial conditions with uniformly 
distributed hydro particles and a smaller, also uniformly distributed, star 
particle box in the center such that the hydro particles close to the faces of 
the box have no star neighbours.

Furthermore, the run is set up such that each time step all particles are 
active, and each time step an output is generated. This is necessary for the 
'./rt_uniform_box_checks.py' script to run successfully.

The `./rt_sanity_checks.py` script tests some general properties of the RT 
debug scheme, and any simulation run with this particular RT scheme should 
pass the tests therein. 

The `swift_rt_debug_io.py` contains IO routines for the debugging output that
is used by the other scripts.

The python scripts with the suffix `-GEAR` do the same as the other scripts, but
are made to test the GEAR RT scheme. Debugging checks must be enabled in the run
in order to create the appropriate outputs (`--enable-debugging-checks`). The
scripts and parameter files for GEAR are written for 4 photon groups, so compile
swift with `--with-rt=GEAR_4`.

Tl;dr: 
    - `./rt_uniform_box_checks.py` only works for this example
    - `./rt_sanity_checks.py` is made to work on any run with the RT debug scheme

    - `./rt_uniform_box_checks-GEAR.py` only works for this example with the
      GEAR scheme with debugging checks enabled
    - `./rt_sanity_checks-GEAR.py` is made to work on any run with the GEAR
      scheme and debugging checks enabled.