Two strange results

1.  After a few iterations, the electron density will sometimes become
non-symmetric about the middle of the domain, which leads to negative
eigenvalues
2.  Sometimes a small perturbation in the middle of the well will
completely kick electrons out to either side of the well and invert the
charge density, effectively creating a deeper well and giving negative
energies as well
adding multigrid solver support
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/solvers/PoissonSolver.java
	src/solvers/SORSolver.java
	src/testing/MainTest.java
	src/utils/WellParameters.java