I should've commited before, but I wanted to make things compile.
The big change is that I've added a global time step so the parameter
does not need to be passed in each function. This is useful as we are
moving towards using time profiles for boundary conditions and injection
of particles (not in this branch, but in the future and the procedure
will be quite similar)
Probes are now written at the 0 iteration.
Additionally, and this shouldn't be done, some small changes to the quad
elements. This should be done in a separate commit, but I'm lazy.
Now, probes check all particles in the domain.
This is done only when probes are outputed to save CPU time.
However, still some issues and distribution functions are not properly
being calculated.
The code nows offer the possibility to obtain the distribution function
for a specific species in a 3D velocity grid at a determined position.
This is a simple method that just scatter the particles in one cell into
the velocity grid.
