Create file with conservation laws

[mlliarm]

Implement the rules that correspond to the conservation laws inside the laws.pl script:

• Conservation of energy (since the mass is in GeV/c^2, the energy equals arithmetically to the number of the mass. No need for calculations. We're assuming that the particles are not moving.)
• Conservation of charge
• Conservation of leptonic numbers l_e, l_mu, l_tau
• Conservation of baryonic number B
• Conservation of strangeness S
• Conservation of spin
• Combine them in a general rule that checks if all conservation laws are being conserved

[mlliarm]

Sketch of implementation of the conservation of charge:

1. Get the first/last element from the Input_particles list
2. Get the first/last element from the Output_particles list
3. Calculate sum of charges of input particles recursively
4. Calculate sum of charges of output particles recursively
5. Check if those two values are equal
6. Recurse the charge_is_conserved relation so that you get all the particles
   from each list.

I might be missing a step or haven't thought things right.

[mlliarm]

The main idea of the conservation of charge is the following:

1. Create a rule to calculate the total charge of a list of particles.
2. Create a second rule that has as input two lists In and Out, one for the input particles and one for the output particles. Use the predicate (1) to calculate the total charge for each list. At the end compare the sums.

I'll use the same idea in the rest of the conservation rules, when usual arithmetic is being applied. Pay extra care in the conservation of spin, as the physics might require different manipulations there (research more).