System.*: Added functions for checking bound.

Added bool for ability to check only potential energy from bound
objects.
main.cpp: Removed whitespaces from progress, made newline.
Restructure: Lost loops and made energy fields.

Each particle now has fields containing the current energy.

System has method for updating energies in all particles. This is done
once per time step.

When fetching energy: Fetch from particle and don't use the calculate
methods in system.